Thanks for the feedback! I spend so much time looking at the game that it all kind of blends together after the first thousand hours, so it's nice to have someone else take a stab at it.
The flashbang is odd but I can try to replicate it, or at least I'm aware of what to look for. Is it possible the Ninja and another character had the Linked buff, and it applied to both of them? Currently the only way to apply that is with the Engineer, so no enemy could have done it, it would have to be something you chose to do.
I thought I had removed the ability for player input during a card being discarded, but my guess is with the Hacked Pistol in particular it's allowing input during the turret activation. Thanks for the report! That type of issue is such an edge case that I doubt I'd have ever found it on my own.