I don't think so. It was my third buff in total, feels like it just gave nothing at all, either that or it is giving the additional +1% but it's not showing it.
For what it's worth, other buffs seem to be showing up and stacking just fine. It's just that one specific buff.
I see it too!! I am on Stage 1, and I just rolled a disco ball buff, and it's showing as 1%. But in editor it is 0.5. So I will write up that bug. Sorry for the confusion! I think it's a display issue where the number is rounding? Or something like that...