Why is my Animation not Retargeting Correctly?

I have a model that has many animations working fine. I am trying to add an additional FBX animation into the animator for the model (that originally belonged to another model) and it previews fine (when I drag my model to the preview window). But when I go to the animator and add the animation, the preview there, the model is stuck in the T Pose but still animates movement of the entire model.

Correct preview:

correct in preview (When I click the animation clip in the project)

Incorrect in animator and in the game:

incorrect in animator/game

I have spent several hours importing it as humanoid, swapping avatars and masks, but no luck.

Currently set as humanoid, create from this model:

alt text

You can see the preview here is fine, but here it is not:

alt text

Any help is appreciated!

Another followup for anyone who may run into this issue… I am pretty sure the cause is mixing generic animations and humanoid animations in the same animator. One seemily unrelated (non active) generic animation can cause the whole thing not to work. After remaking the entire animator I still had a problem where no matter what they were stuck in TPose. I fixed it because I found 1 animation that was set at generic instead of humanoid. I had swapped back and forth on animation import types all day yesterday so it went unnoticed.