I'm pretty sure this is what happened. I was happily farming FG, then when I tried to play an hourglass I accidentally clicked mitosis. The instruction for me to choose the target then popped up, but I didn't quite notice it, so I see my hour glass was not played, so I clicked the hourglass again, this time succeeded in playing it while the targetting instruction is still there. I then clicked cancel, but instead of the mitosis, another hourglass appeared in my hand. I proceeded to play the hourglass then noticed that I have 5 hourglasses in a deck packed with only 4. As for the mitosis? it completely disappeared.
