Mesh doesn't get animated when set to Cast Shadows Only

Hey everyone, first question here: I've set up a Character with animations that I'm planning to use only to cast shadows for my first-person view (so you can see your own shadow but not the player model).

When my character mesh is set to Cast Shadows on, it works just fine and the walk/idle animation play. The problem is when I switch it to Cast Shadows only, the animations seem to be disabled or are not getting picked up, my character is stuck in the T-pose.

I've tried setting "Update When Offscreen" on, but it doesn't change it.

Any suggestions on how I can get this to work? Thanks in advance.