Vulpera heritage armor backpack bug

I tried searching the forums to see if anyone else had this issue, but I couldn’t find anything. With the vulpera heritage backpack transmogged to the cloak, auto attacking with 2 1h weapons, swinging with the right hand causes the backpack to fly or levitate off the back, hang in mid air, and then snap back onto the back.
Is anyone else having this issue? Is it a known issue? Or is it normal to have a loose rubber banding backpack? Ive tried this with an enhancement shaman and a frost DK, auto attacking, and every time the right hand swings, the backpack flies off.
Im starting to think maybe I’m the only one with this issue…

I have the same issue as well.