SMB share can copy but not move

[DJArbz]

This has worked in the past.
I am working on my media workflow after some negligence since last summer/fall.
I've noticed that I can copy a file from a source dataset to a destination dataset via SMB mount, but I am unable to move.
Attempting to move provides an I/O error.

If I login to the shell as the same user, the move operation works without issue, so I believe this is directly related to the share.
If I mount the share on a Windows machine, I see in the file/folder properties, the Read Only option is checked.

I have Everyone set to full access on the Share ACL and the Filesystem ACL is as follows.

owner@	root	Allow	Full Control
group@	root	Allow	Modify
User	root	Allow	Modify
Group	root	Allow	Modify
User	plex	Allow	Full Control
Group	plex	Allow	Full Control
Group	builtin_users	Allow	Modify
Group	builtin_administrators	Allow	Full Control

The Plex user is what I am mounting the share as and previously was set to Modify, but I changed to Full Control for testing.
I am able to touch a test file and move it just fine, so it appears to just affect existing files.

Code:

# File: <REDACTED>
# owner: 3000
# group: 0
# mode: 0o100770
# trivial_acl: false
# ACL flags: none
            owner@:rwxpDdaARWcCos:------I:allow
            group@:rwxpDdaARWc--s:------I:allow
         user:root:rwxpDdaARWc--s:------I:allow
        group:root:rwxpDdaARWc--s:------I:allow
        group:plex:rwxpDdaARWcCos:------I:allow
group:builtin_users:rwxpDdaARWc--s:------I:allow
group:builtin_administrators:rwxpDdaARWcCos:------I:allow
         user:plex:rwxpDdaARWcCos:------I:allow

I have not seen anything pertinent in /var/log/messages or /var/log/samba4/log.smbd.