Character Hands Stuck in Place during Animation

Hi all, here you can download the Blender file:

I designed 19 animations for the ape, listed below with notes. (L = left, R = right).

Chest beat
Climbing L hand up
Climbing R hand up
Move left R hand up
Move right L hand up
Swing left L hand up
Swing right R hand up*
L eat L hand down
L eat L hand up
R eat R hand down**
R eat R hand up*
L punch L hand down
L punch L hand up
R punch R hand down**
R punch R hand up
Fall swing L*
Fall swing R*
Fall swing fall L*
Fall swing fall R*

*These 5 don’t export with the FBX for some reason. If you have any idea why, please let me know.

**These are having the issue where the hands of the ape seem to be stuck in place. I think it has to do with the IKs I applied, but not sure. I discovered a fix in Blender: switch to one of the “climbing” animation, then switch back to one of these. It should fix the problem in Blender. However, in Unity these animations retain the “stuck hands” problem.

There is one other issue I’m having with a glitch or something in the legs during certain animations. I made another post about it:

Any help would be much appreciated!