ShiroUmi

It isn't bugged, but a bit tricky for you since the quest strictly require you to go 1 > F grab > Z, so if your 1 accidentally procs critical which lead into F changes into Knee instead of grab, you will have to do it all over again. Also, don't forget to "Gain distance from the ploggle", which also affect whether you will get credit for the quest or not. Check this Destroyer player below, he also had the same problem as your until he did the "gain distance from the ploggle".