Changing RootJoint's C0/C1 position causes a weird glitch

So i tried to make a look system for r6 rigs, and it worked pretty well, until i activated shiftlock and jumped backwards. as shown in the video, this causes the character to act weird while jumping backwards, moving sideways a bit. very weird. this also happens when i change the C1’s position as well. Any help?

i’m very sorry i have to bump this. i posted it very late. any help is still appreciated.