u/BryceFtw

I'm currently sitting at the Martial Art Mastery II Challenge for the Bellstrike Umbra Path and no matter what i do, it doesn't seem to register anything.

I always have Spring Surge / Riverflow buff up before casting the "sweep all" Skill. The defence reduction debuff is on the Twin Lion but nothing happens. I also tried the spears charged skill but to no success also.

Does anyone know what to do, or is this currently a bugged challenge?
Thanks for you help!