For some reason my model has their knees twisted 90º once imported into the game. I've tried to move the skeleton around in edit mode in hopes of fixing it but nothing really seemed to affect it. In both blender and the tool itself the rigging appears to work fine so I cant really tell whats causing it. Only thing I can think of is maybe the weight painting is messed up somewhere or I'm doing something wrong with the tool.

This is how they show up ingame.

Meanhile in blender and the tool they look and move like this.

I'll leave the files for the project here.