Potential Bug with Secret Dungeons?

Sorry if this maybe isn't news to you folks, but I just realized that if you finish a wave with atk buff, the buff won't count down upon going to the next stage for SDs. I don't know how to phrase it properly, but heres where I noticed it:

Galleon TTL -> Lushen amps with 2 turn atk buff, killing the entire wave -> Game progresses to the next stage -> Lushen attack bar resets, but he still has 2 turn atk buff.

It might work for other buffs, I don't know. Doesn't seem like an intentional error though?