I found a glitch: moon lord drift?

So i decided to farm moon lord for a lunar portal staff on my summoner character. thing is when i killed it, it went up and right instead of just up. the actual direction depends on where it was going when i killed it. this didn't happen to me before the new patch, and isn't mentioned in the changelog. is this a bug?

edit: it does not seem possible to get it to drift down.