RHEL 10's current cronie packages have a bug that was apparently introduced on upstream cronie-1.6.1 and was present until 1.7.0. In these versions (including the ones present on RHEL 10), cronie's emails (generated from cron jobs) have an empty MAIL FROM address:

Jan 12 14:04:01 r100 postfix/qmgr[1185]: 6877C209E422: from=<>, size=901, nrcpt=1 (queue active) 

Setting MAILFROM in the crontab is ignored so there is no easy way to fix this (without potentially affecting other email on the system, such as bounces).

Certain mail infrastructure products may reject these emails, so this would need to be fixed in RHEL.

This appears to have been caused by: https://github.com/cronie-crond/cronie/pull/118 

The upstream report can be found here: https://github.com/cronie-crond/cronie/issues/166

From the upstream report, it would seem this has already been fixed, so a backport/rebase would be needed.