So, I had just won a pack from arena. What I did was I spam-clicked on the pack, but never dragging it to the center of the screen to open.
I would:
1. Spam click
2. Drag the pack a little like an inch.
3. While spamming clicking/moving the pack, I hit spacebar.
The pack will open, but you will still have a pack left like you never opened it! When you open the phantom pack, the cards will hoover, but you can't click on them.
Anyway to get cards from this phantom pack? Or does the server know it's a pack you're not supposed to have?
I haven't tried this with more than 2 packs. Anyone have more than 2 packs to test it with?