I've been able to test it 3 to 4 times now. But as far as i can tell when ever i play Jhin in summoners rift and Jayce is also in the game Jhin's Deadly Flourish sound effect is layered with Jayce's Shock Blast. Meaning that when i press W with Jhin in a game it will create the sound for Jayce's Q. It only happens when Jayce is in game though
During champion/skin production sound effects are often stolen from other champions as placeholders until the new SFX are finished and implemented. It's entirely possible (in fact, it's happened before) that someone forgot to remove the call to the placeholder sound. So whenever that sound would be loaded due to the presence of the champion it was borrowed from, it overrides or stacks with the intended sound.
Nice catch.
Bump for awareness, it happened again. i have tested it with successful results almost 6 times now
