[Gameplay] Bard Meeps don't trigger Sheen effect

I am not 100 % certain that this is a bug and not intended behaviour, but it is different from what I would expect by the description.

So in short: After you made an attack with a meep exploding I would expect that the next attack would have the sheen effect on it, but that is not the case. Is this a bug or destined behaviour? It seems a bit odd to me.