http://community.cambiumnetworks.com/t5/PMP-450/PMP-450-hell-on-FM-tower/m-p/36502 is one of the previous discussions (2014) on the subject of FM causing ethernet trouble. We very rarely have trouble with that now since rolling out the use of the ferrite rings.
We've not (yet) seen any problems on the RF side with the APs, just the ethernet side.
j