The damage in combat is unstable

[Blulotus]

I have a pineco lv89. I used to be able to 1 hit Misdreavus lv47 using Payback. However, after the maintenance, i need 2 or 3 hits to knock out the wild Misdreavus. Besides that, my pineco sometimes needs 4 - 5 hits (payback) to kill a lv47 Graveler, but there are times that it can one hit the graveler lv47 using Payback.