Why are some cards randomly malfunctioning in TCG LIVE?

I just had a game where I played Adventurer's Discovery. For some reason although I had 3 Pokemon V/Vstar available (one in prize cards) to choose from, it would ONLY allow me to select the Vstar (Giratina Vstar) and would not allow me to add the 2 Pokemon V (Giratina V) to my hand. Clicking/dragging on the two Pokemon V did nothing; they wouldn't go into the selection boxes. I've had this problem with other cards at other times including with Lady which would only let me select one energy instead of 4 - clicking on any other energy did nothing. For context, the only thing I could select was the last card in the list of selectable options each time it happened. Any idea what's causing this? This only happens randomly; it does not occur in every game. I think it's happened a total of like 4 times that I recall. This time it caused me to lose the game when I shouldn't have lost.

I'm not sure if it's important but the opposing active pokemon was Entei V, with a Chien Pao ex on the bench.