Stopped working as in, clicking on the slot doesn't do anything? Just to double check, do you still have enough Quartz to spin? If you've got enough and it's still unresponsive, that might be a bug. I'll try to reproduce it on my end and see if I can track it down. Thanks for the heads up!
I had 64 quartz when I clicked on it and it was unresponsive, I had to refresh the page for it to work ; I have an habit of spam clicking, so that might have caused the issue,(maybe I accidentaly clicked on the item menu on the top right or the achivement thingy while it was spining)
I tried spamming clicks and clicking around randomly during spins too, but I haven't been able to reproduce the issue yet. I'll keep testing to see if I can trigger it. If it happens again on your side, let me know. Any extra clues will help narrow it down :)