Platform, device and operation system
Android, Samsung Galaxy Note S7+, Android 11
What were you expecting to happen, and what actually happened
I cast Gravedigger, and some gems were destroyed and skulls were created while new gems were falling. A trio started flashing as if they will be matched on my next turn, even though they do not match. I have a screenshot, but apparently I am not allowed to embed media in a post.
How often does this happen? When did it begin happening?
It has happened twice now, but it does take some (bad) luck.
Steps to make it happen again
Cast Gravedigger, and have one of the created skulls break up a match created by the gems that fell to replace the column(s) that were destroyed.