I don't know if this is simply because of an influx of new people on already busy servers or not. I notice this even on the emptiest servers.
There is a delay to cards on the choose screen during battle.
I have a pretty balanced deck so I can take on any situation. So sometimes I just need to discard most of my cards to get the ones I want. No biggie it's the price I pay to keep cards I MAY need in there.
Problem is I often discard the ones I need because of a glitch delay. I click on the right card to discard but due to some delay it actually chooses the card I wanted to keep. There is no undo to discards (Which there should be but only for the round your discarding them in).
Another problem is that sometimes I choose a card and it acts as if I didn't. I can see on the bottom that it has the card I choose assigned to me but then the round ends after the time runs out and it acts as if I picked nothing.
This is just annoying beyond belief and in some cases fatal to my character in a battle.