I found this bug while I was trying to save scum after noticing a mistake too late, but the game softlocked me afterwards, forcing me to start a new run even after reloading the game.
I had a double tag from the Anaglyph Deck, and skipped a blind to give me two Etherial Tags (spectral pack).
I realised I should've sold my Delayed Gratification joker before choosing to make one negative, so exited after opening pack one, sometimes this lets you undo what you just did if you're fast enough.
Upon continuing my run, it opened the second spectral pack, but unfortunately the pack had no cards within it. I reloaded the game and this still happened.
I was ready to cut my losses but the skip button is greyed out and unusable. This would be much more annoying if i was further in my run, but still is an annoyance.
STEPS TO REPLICATE:
1: Have a double tag
2: Skip a blind to obtain two booster pack tags (Standard, Charm, Meteor, Buffoon or Etherial Tags should all work, but I haven't tested all 5)
3: Open the first pack fully and open the main menu before the last pack opens
4: Continue run and no cards will open in pack, not letting you skip or continue from that point, forcing you to start a new run.
In getting a clip to demonstrate this bug, I have noticed that if you have two double tags (easy with the Anaglyph Deck) and skip to get 4 packs, trying to do this trick will instead give you the same cards and give you one less pack total.
The bug where you get no cards, softlocking your run, only seems to happen if you have one tag left.
Clip has been muted as it was done while in a call, but should be a good demonstration of both the described issues.
The game speed might make this easier/harder to replicate, or maybe it only happens at faster speeds. For my testing I did it in 2x speed, not too sure how the speed works behind the scenes but I thought best to mention.
Love the game, thanks for all the work you do :)