Game says I have 8 cards in hand

[Onizuka]

The game tells me I have 8 cards in my hand, even though I have 7. Prevents drawing with Hourglass, stating I have 8 cards in my hand.

[pikachufan2164]

This is a known bug.

9.  Rapid Draw problems
Symptoms:  Not drawing a card you should have, despite having room for it in hand.  Being forced to discard an invisible 99 cost card.
Causes:  If you use card draw abilities like mind gate, electrum hourglass, and precognition, too close together, an error occurs.  If you are looking at extended card art by mousing over a card while a card is drawn, that card will magically disappear.  As the game keeps track of your cards in hand separately, the game will think you have an extra invisible card in hand, and force you to discard it if necessary.