If you select Gun Slinger on your character move while there is no active targets (grey choices) in view they system hangs, you can not switch character, weapon or do anything except scroll around the screen, the only way out is to quite back to the loader and relaunch the game.
It is sometimes true for ‘Fire’ ability. When you press ability to quickly when changing characters.
I haven’t done that yet, but I am sure the code can be an easy fix on these ones?
Don’t ask me. 
I’m not connected to Snapshot Games in any way other than making pre-order for Phoenix Point… Whoa! 2 years ago. Some claim otherwise because I’m quite active on this forum.
I suppose devs would need to check some conditions resetting the camera or the UI after selecting first person targeted abilities.