We all know the animation bug about some cards becoming smaller than others... now i present the oposite: card would stay that way
I get that sometimes even when spectating, different cards. Often it's armour cards. Happens when you're clicking the mouse fast during card animations (Pause Enemy Cards option on).
Noting here that I got that on test server (in a ranked game) and it was quite annoying since there was a card I wanted to play behind the big card and now I couldn't play it. I definitely clicked through animations and since I was freshly out of tutorial many cards were still "new" to me and I had this "pause new cards" on. So that's a possible reason. Anyway it went away the same turn after my character whose card it was was attacked since the big card was an armor card that got to roll agaisnt the attack.