This was in PvP1. As you can see from the screenshot, my deck has the right amount of cards and I actually draw cards (and see the drawing animation and the card I draw), but I can't click any of the cards in my hand, forcing me to discard a card from the 8 cards I could not click. I'm not entirely sure what happened after I let myself time out...
Some interesting things to note is that I was using fast AI speed and there was very little delay between me finishing my turn and my opponent playing his turn, which is why I suspect this was a desync error.