So I was playing in execution looking at the new map, and I changed mercs once, and then I was unable to change mercs again for the entire game. F1, F2, F3 did nothing what-so-ever. I changed servers and maps and was able to swap mercs once, but after 1 round the bug persisted.
Bug was also present in Stopwatch. As soon as I swapped from one merc to the next I was unable to swap again.
Bug was also present in Objective. As soon as I swapped from 1 merc to the next I was unable to swap again.
Upon further testing, F2 does nothing at all for me since patch, and whatever merc I have in the F2 slot in my squad I am unable to swap to period.
I have talked to several other players in game who have had the same issue as me since the update and it seems like it is pretty random as to who it effects as some people have it, and some do not.
I tried multiple squads with different mercs and the problem was there regardless.
It is even present after closing the game and relaunching multiple times.