In the turn, is the key
The TCAS signal can be blanked by the airframe whilst in the turn.
So the logic of removing the bank is a valid one, but not perhaps the correct response in most circumstances.
So if both aircraft are banked, it is just possible that the signals could both be blanked, then I believe the TCAS logic defaults to RA mode.
One other aspect: does the data transfer rate increased whenever a TA is instigated, and then increased again between the "conflicting" RA traffic.
glf