@tensi0n - Did you ever file that bug report?
@Kris Moore - Did anyone else report this issue?
What happened with this issue?
I've ran into it myself...
	
		
			
		
		
	
	
		
			
		
		
	
I too can add the three missing disk to a new pool, in the pool manager, as shown in "truenas issue2.jpg" screenshot.
I've attached the output of 
geom disk list and 
zpool status -v.
As you can see, ada0 and ada1 are acutally SSDs, not HDDs.
Also, ada2, ada3 & ada4 don't actually "exist", they should be da0-da5.
The only thing I can think that may have caused it:
1. I did a fresh install of TrueNAS
2. Setup the SSDs as a mirroed boot pool ada0p2 and ada1p2
3. Used the remaining space (ada0p3 and ada1p3) as a mirroed storage pool
4. Restored a config file from a different hardware setup, from which I just moved the 6 HDDs
My thought is that something from the previous setup/config got imported and overwrote the correct (new) config.
Any idea what could be wrong?
-------------------
EDIT:
I just added the output for both 
midclt call disk.query and 
midclt call -job disk.sync_all commands.
It seems that when I run the second command, it fails and spews some errors regarding the middleware python package.
I found these two commands in this bug report from last year that details a similar issue:
TrueNAS | NAS-105996 | UI: Storage > Disks: missing disk - but correctly reported in pool status
Possible related errors:
I've also attached my debug file.
-----------------
geom disk list
Code:
root@truenas[~]# geom disk list
Geom name: ada0
Providers:
1. Name: ada0
   Mediasize: 250059350016 (233G)
   Sectorsize: 512
   Mode: r2w2e5
   descr: Samsung SSD 860 EVO 250GB
   lunid: 5002538e4969cc67
   ident: S3YJNX1M608874M
   rotationrate: 0
   fwsectors: 63
   fwheads: 16
Geom name: ada1
Providers:
1. Name: ada1
   Mediasize: 250059350016 (233G)
   Sectorsize: 512
   Mode: r2w2e5
   descr: Samsung SSD 860 EVO 250GB
   lunid: 5002538e497953e1
   ident: S3YJNX0M741744E
   rotationrate: 0
   fwsectors: 63
   fwheads: 16
Geom name: da0
Providers:
1. Name: da0
   Mediasize: 6001175126016 (5.5T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA ST6000VN0033-2EE
   lunid: 5000c500c2e8096c
   ident: ZAD98P31
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255
Geom name: da1
Providers:
1. Name: da1
   Mediasize: 6001175126016 (5.5T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA ST6000VN0033-2EE
   lunid: 5000c500c2e7d37c
   ident: ZAD98PRK
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255
Geom name: da2
Providers:
1. Name: da2
   Mediasize: 6001175126016 (5.5T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA ST6000VN0033-2EE
   lunid: 5000c500c29b374f
   ident: ZAD93KHP
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255
Geom name: da3
Providers:
1. Name: da3
   Mediasize: 6001175126016 (5.5T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA ST6000VN0033-2EE
   lunid: 5000c500c2db0ef9
   ident: ZAD97RRQ
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255
Geom name: da4
Providers:
1. Name: da4
   Mediasize: 6001175126016 (5.5T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA ST6000VN0033-2EE
   lunid: 5000c500c2d6065e
   ident: ZAD97WY1
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255
Geom name: da5
Providers:
1. Name: da5
   Mediasize: 6001175126016 (5.5T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA ST6000VN0033-2EE
   lunid: 5000c500c2e7a0e4
   ident: ZAD98JVD
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255
 
zpool status -v
Code:
root@truenas[~]# zpool status -v
  pool: boot-pool
state: ONLINE
  scan: resilvered 1.14M in 00:00:08 with 0 errors on Mon Aug  9 10:47:13 2021
config:
        NAME        STATE     READ WRITE CKSUM
        boot-pool   ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            ada0p2  ONLINE       0     0     0
            ada1p2  ONLINE       0     0     0
errors: No known data errors
  pool: ssd
state: ONLINE
config:
        NAME                                            STATE     READ WRITE CKSUM
        ssd                                             ONLINE       0     0 0
          mirror-0                                      ONLINE       0     0 0
            gptid/6ddbf6b4-f8ef-11eb-afa2-002590b5331b  ONLINE       0     0 0
            gptid/7016c503-f8ef-11eb-afa2-002590b5331b  ONLINE       0     0 0
errors: No known data errors
  pool: tank
state: ONLINE
  scan: scrub repaired 0B in 12:24:29 with 0 errors on Mon Aug  9 09:49:41 2021
config:
        NAME                                            STATE     READ WRITE CKSUM
        tank                                            ONLINE       0     0 0
          mirror-0                                      ONLINE       0     0 0
            gptid/00ece65b-e3fc-11eb-aa57-d485646a6b67  ONLINE       0     0 0
            gptid/0119ab6e-e3fc-11eb-aa57-d485646a6b67  ONLINE       0     0 0
          mirror-1                                      ONLINE       0     0 0
            gptid/0157c9f9-e3fc-11eb-aa57-d485646a6b67  ONLINE       0     0 0
            gptid/016508f7-e3fc-11eb-aa57-d485646a6b67  ONLINE       0     0 0
          mirror-2                                      ONLINE       0     0 0 
midclt call disk.query
Code:
root@truenas[~]# midclt call disk.query
[{"identifier": "{serial_lunid}ZAD97RRQ_5000c500c2db0ef9", "name": "da3", "subsystem": "da", "number": 3, "serial": "ZAD97RRQ", "size": 6001175126016, "multipath_name": "", "multipath_member": "", "description": "", "transfermode": "Auto","hddstandby": "ALWAYS ON", "hddstandby_force": false, "advpowermgmt": "DISABLED", "acousticlevel": "DISABLED", "togglesmart": true, "smartoptions": "", "expiretime": null, "critical": null, "difference": null, "informational": null, "model": "ATA ST6000VN0033-2EE", "rotationrate": 7200, "type": "HDD", "zfs_guid": "8450599037489905515", "devname": "da3", "enclosure": null, "pool": null}, {"identifier": "{serial_lunid}ZAD98PRK_5000c500c2e7d37c", "name": "ada4", "subsystem": "ada", "number": 4, "serial": "ZAD98PRK", "size": 6001175126016, "multipath_name":"", "multipath_member": "", "description": "", "transfermode": "Auto", "hddstandby": "ALWAYS ON", "hddstandby_force": false, "advpowermgmt": "DISABLED", "acousticlevel": "DISABLED", "togglesmart": true, "smartoptions": "", "expiretime": null, "critical": null, "difference": null, "informational": null, "model": "ST6000VN0033-2EE110", "rotationrate": 7200, "type": "HDD", "zfs_guid": null, "devname": "ada4", "enclosure": null, "pool": null}, {"identifier": "{serial_lunid}ZAD93KHP_5000c500c29b374f", "name": "ada3", "subsystem": "ada", "number": 3, "serial": "ZAD93KHP", "size": 6001175126016, "multipath_name": "", "multipath_member": "", "description": "", "transfermode": "Auto", "hddstandby": "ALWAYS ON", "hddstandby_force": false, "advpowermgmt": "DISABLED", "acousticlevel": "DISABLED", "togglesmart": true, "smartoptions": "", "expiretime": null, "critical": null, "difference": null, "informational": null, "model": "ST6000VN0033-2EE110", "rotationrate": 7200, "type": "HDD", "zfs_guid": null, "devname": "ada3", "enclosure": null, "pool": null}, {"identifier": "{serial_lunid}ZAD98P31_5000c500c2e8096c", "name": "ada2", "subsystem": "ada", "number": 2, "serial": "ZAD98P31", "size": 6001175126016, "multipath_name": "", "multipath_member": "", "description": "", "transfermode": "Auto", "hddstandby": "ALWAYS ON", "hddstandby_force": false, "advpowermgmt": "DISABLED", "acousticlevel": "DISABLED", "togglesmart": true, "smartoptions": "", "expiretime": null, "critical": null, "difference": null, "informational": null, "model": "ST6000VN0033-2EE110", "rotationrate": 7200, "type": "HDD", "zfs_guid": null, "devname": "ada2", "enclosure": null, "pool": null}, {"identifier": "{serial_lunid}ZAD98JVD_5000c500c2e7a0e4", "name": "ada1", "subsystem": "ada", "number": 1, "serial": "ZAD98JVD", "size": 6001175126016, "multipath_name": "", "multipath_member": "", "description": "", "transfermode": "Auto", "hddstandby": "ALWAYS ON", "hddstandby_force": false, "advpowermgmt": "DISABLED", "acousticlevel": "DISABLED", "togglesmart": true, "smartoptions": "", "expiretime": null, "critical": null, "difference": null, "informational": null, "model": "ST6000VN0033-2EE110", "rotationrate": 7200, "type": "HDD", "zfs_guid": "1925182301347828445", "devname": "ada1", "enclosure": null, "pool": null}, {"identifier": "{serial_lunid}ZAD97WY1_5000c500c2d6065e", "name": "ada0", "subsystem": "ada", "number": 0, "serial": "ZAD97WY1", "size": 6001175126016, "multipath_name": "", "multipath_member": "", "description": "", "transfermode": "Auto", "hddstandby": "ALWAYS ON", "hddstandby_force": false, "advpowermgmt": "DISABLED", "acousticlevel": "DISABLED", "togglesmart": true, "smartoptions": "", "expiretime": null, "critical": null, "difference": null, "informational": null, "model": "ST6000VN0033-2EE110", "rotationrate": 7200, "type": "HDD", "zfs_guid": "12915272379188220704", "devname": "ada0", "enclosure": null, "pool":  null}]  
midclt call -job disk.sync_all
Code:
root@truenas[~]# midclt call -job disk.sync_all
Status: (none)Total Progress: [________________________________________] 0.00%
expected string or bytes-like object
Traceback (most recent call last):  File "/usr/local/lib/python3.9/site-packages/middlewared/job.py", line 367, in run    await self.future  File "/usr/local/lib/python3.9/site-packages/middlewared/job.py", line 403, in __run_body    rv = await self.method(*([self] + args))  File "/usr/local/lib/python3.9/site-packages/middlewared/schema.py", line 973, in nf    return await f(*args, **kwargs)  File "/usr/local/lib/python3.9/site-packages/middlewared/plugins/disk_/sync.py", line 151, in sync_all    await self.middleware.call('enclosure.sync_disk', disk['disk_identifier'])  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1248,in call    return await self._call(  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1216,in _call
    return await self.run_in_executor(prepared_call.executor, methodobj, *prepar
ed_call.args)
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1120,in run_in_executor
    return await loop.run_in_executor(pool, functools.partial(method, *args, **kwargs))
  File "/usr/local/lib/python3.9/site-packages/middlewared/utils/io_thread_pool_executor.py", line 25, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 217, in sync_disk
    enclosure, element = self._get_slot_for_disk(disk["name"])
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 164, in _get_slot_for_disk
    return self._get_slot(lambda element: element["data"]["Device"] == disk)
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 152, in _get_slot
    for enclosure in self.middleware.call_sync("enclosure.query", enclosure_query or []):
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1275,in call_sync
    return methodobj(*prepared_call.args)
  File "/usr/local/lib/python3.9/site-packages/middlewared/schema.py", line 977, in nf
    return f(*args, **kwargs)
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 70, in query
    for enc in self.__get_enclosures():
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 342, in __get_enclosures
    return Enclosures(self.middleware.call_sync("enclosure.get_ses_enclosures"),
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 362, in __init__
    enclosure = Enclosure(num, data, stat, system_info)
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 413, in __init__
    self._parse(data)
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 417, in _parse
    self._parse_freebsd(data)
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 436, in _parse_freebsd
    self._set_model(data)
  File "/usr/local/lib/middlewared_truenas/plugins/enclosure.py", line 537, in _set_model
    elif MINI_REGEX.match(self.system_info["system_product"]):
TypeError: expected string or bytes-like object