Hey,
I have been testing this with some of the team, and the % chance increase to Crits is calculated based on how many Yellow Gems are on the board after any have been removed from Gem Matching and not based on how many are on the board prior.
As these are removed from the board after matching, to provide Mana thus reducing the number of Gems to calculate an increase to % crit chance.
I’ve spoken to the designers and the resolution order of the Spell was taken into consideration during the design phase, so the Spell is currently balanced as intended.
I will pass feedback onto the team regarding the wording of the Spell description though.
Jeto (she/they) - Support Human 