At 15th day when i start second "action sequence" i get this red card on middle of screen, pressing confirm tells me that my agility has been increased, but then i'm stuck with black screen (i can still hear music and sound though)

Yeah, that should definitely not be happening. I’ll poke around and see if I can figure out what’s up.
I’m going to guess that what happened was that you accidentally clicked the middle card area after confirming a card event but before all the handling for card selection finished getting cleared out, so I’ll see if I can’t adjust the handling of that for the next patch.