Hey

It's not a bug.

It's the interaction with Barrier-Casted Mysteries.

Barrier Mysteries are double cast, meaning they have two interactions. If a barrier is cast upon another barrier, the previous one will be canceled.

However, the interaction with the same barrier from the same character will outright just cancel it because the priority comes from its cancel effect.
It's not a bug, more of a game design.

Hopefully, that helps!

It is happening too with Hashirama's Mystery Skill, when you use his Mystery and created a barrier, after the cooldown, there's a chance that his Barrier will not disappear, and when you use his Mystery, instead of putting up the barrier again, which in this case didnt disappeared from the previous usage, the barrier will be gone and you will need to wait again to cooldown to cast it again ..