Custom Rig Animation problem

I’ve rigged the model, added the HumanoidRootPart, and made the rig type R6 and this is happening and I have no clue why

robloxapp-20210527-1630365.wmv (567.9 KB)
Video: robloxapp-20210527-1631036.wmv (411.6 KB)

It only happens when it’s being animated too?