The wifi and cellular going flat would indicate to me more bad reception/sealed room than interference/induction, though this is possible. Ferrite beads/chokes, IMHO, are not the cure all that many seem to think.
What are the addresses for the cards/annunciator? Are they "binary bits" close?
I would recommend having you and the distributor getting together with FCI tech support and talking this out. I am not a fan of the "shotgun" approach that was taken in this case.
Was shielded wire used? Is it terminated properly? Can't remember if it was an FCI requirement or not. If so, try removing the shield termination and play with taking it to ground. May make the situation worse, but may also help.
I know you "
" on the Notifier, but until you figure out what is going on, the problem could even get worse, and I like both systems......