As you can see in this photo, my card catalog was full so I used 30 Crystal to expand it. The game then used both 30 crystal and all my remaining royal crystal.
Noticed the text, I immediately opened F4 shop to check, my Royal Crystal was still there, but when I closed the shop, a text “You accquired Royal Crystal x4,100.” popped up, together with the icon of Royal Crystal x4100 in the middle of the screen.
So I did not actually lose anything (as of now.) Not sure what this bug is, but what if I didn’t notice and log off before opening shop? My Royal Crystal could be gone for real, because they were only refunded after I opened the shop. Using Crystal shouldn’t have anything to do with Royal Crystal at all.
Thanks for reading.