[GAMEPLAY] Gangplank's Cannon Barrage

During a butchers bridge match I played today as Gangplank, I ran into an issue with his Ultimate Cannon Barrage. I had fired off Cannon barrage as I died, and its cool down had reset. I was unable to use the spell despite it saying it was ready as well as I had no clue as to when it would be ready other than to occasionally press the R button to test it. I was able to fire off cannon barrage in what I will have to assume was at the end of its cool down since I was unable to see when that was. Attached is my log and notes for that match.