well 8.2b4 has a possibility of not having the bug per the bug resolution report (not sure off the top of my head when that version was released, and frankly, I'm whooped right now...
The point was that most recent 8.0.4 had a bug where users other than root could not send mail (at least after my upgrade from 8.0.2, having little to do with cron. If you look at the report, although I initially piped the output of the script that cron called to mail, I tested mail from the command line, which is what blew the errors, and subsequently drove me to make the report, and them to validate the bug.
Sorry if it doesn't apply, I thought it might be related.
good luck