Priority Issue
I was playing against Lathiel, the Bounteous Dawn. During combat I drew activated Zimone and Dina to draw two cards and drew a Final Flourish. After that draw resolved my enemy finished combat, and their second main phase was skipped without providing me with priority. This resulted in Lathiel, the Bounteous Dawn's triggered ability to activate, distributing counters to my opponent's board. I removed Lathiel while this was on the stack by casting Final Flourish, but if priority had not been skipped during the second main phase I would have been able to cast Final Flourish before Lathiel's triggered ability went on the stack. This resulted in a game loss, which impacted my gem rewards from the limited event.