My unusual setup has flushed out a FOV bug that most users may not notice. I play at 5760 x 1080 on triple monitors. To make that look OK, normally you set the FOV slider to something like 140 degrees. However on some games this won't work and instead you modify an .ini file to include AspectRatioAxisConstraint=AspectRatio_MaintainYFOV and then all works perfectly with a normal 70 degree FOV.
That is until the bug raises its head. Whenever the game zooms in for an effect, such as when you do a kill shot or one of your companions does the same, it gets stuck at that zoomed amount and will not return. Very awkward mid battle. Exiting the game and returning solves the issue.
It's possible that for normal video settings, the bug still happens, but the FOV settings make such a small difference you don't notice. But I bet you it's happening...
The game plays flawlessly otherwise. For me though, it's virtually game-breaking...