I have noticed recently that the “Victory” flash appears before my last move was completed.
I’ve seen this as well. Interestingly, the trigger is not obvious. I used Deadpool’s full-on Whales attack a few times on Civil War nodes yesterday, and saw the victory banner before the animation once and after it another time. Both were normal (non-wave) nodes. This may depend on what characters are present on one or both teams.
I think it’s the same problem as reported here: https://forums.505go.com/discussion/44578