This is a very old bug, that seems purely cosmetic, but read on and you’ll see why I think it needs to be fixed.
Sometimes, after you make a match, and new gems are dropping into the gemboard, there is a visual glitch: gems of one color will drop into the board, and then when they settle they will change into gems of another color. I think this bug has existed since the beginning of the game (You can see references to it in some people’s early posts on the forum, for example here and here in 2017)
Recently I discovered a way to make the bug happen consistently: by making a swap that matches a support with the ‘Resilient’ mechanic. The bug occurs consistently when matching the Demonweb Pits support generated by ‘Lolth, Spider Queen’'s abilities, or when matching Wizard Class, or Phenax, God of Deception.
Hopefully making it happen consistently will make it easier to fix!
I believe this bug is almost certainly related to other, infrequently occurring bugs, such as gems which merge the graphics of two different colors of gem, or supports which players lose the ability to click on during a match (which, in the case of Vanguards, renders them unusable). I think it may also be related to general game freezes and crashes caused by gem conversion, which have been plaguing us players for years, often causing consternation and annoyance as they make us lose points in coalition events!
