There's big bug with Frost Queen's Claim(Video Included)

I just found out that there are more than 3 stacks on Frost Queen's Claim. While the Tribute is not in cd, it works normally, but when Tribute is in cd, the stacks won't decrease, and the stacks calculated since the last time this passive is triggered. You guys can see it from my video, TF got so many golds attacking the turrent. I'm pretty sure this is a bug but not a secret surprise*[slayer-pantheon-popcorn]* (For convenience, I took the video in the practice mode, but this is not the problem in practice mode only).