We are in the middle of migrating between Sophos and Defender and have observed a large percentage of our devices don't have the right Defender Configuration profiles required to onboard our devices. Defender has installed fine through policy, but can't work without its settings which are applied via Config profiles.
The Config profiles for Defender on a lot of active machines were discovered to be "Pending" from the Configuration Profiles view within Jamf, but for most Macs, there are no pending Management commands from the Inventory view, and for some they simply sit there indefinitely saying Pending.
I've managed to replicate the problem with really simple config profiles, such as some Finder config, without finding a fix. We've just upgraded to 10.34.0 in the hope it magically fixed things, but it hasn't.
The devices affected are all active, checking in and updating inventory. There's no obvious commonality between devices affected, almost everything comes in through Prestage enrolment, is running Big Sur, Catalina, or Monterey, etc.