Default Animations Broken

I threw in a rigged model from blender, set the rig as Humanoid, and chose a default animation set under the Avatar Descriptor. When in-game, the camera and model move up and down as if the animation worked, but the model is stuck in a T-pose. I’m using the default Avatar SDK (as opposed to 3.0)

The bones are named
Hips
Neck
Head
[Left/Right]UpperLeg
[Left/Right]LowerLeg
[Left/Right]Foot
[Left/Right]UpperArm
[Left/Right]LowerArm
[Left/Right]Hand[Thumb/Index/Middle/Ring/Pinky][1/2/3]
as well as a number of extra bones for hair, based on this image I found on another post.

Are the names of the bones causing the issue? If not, what is?