Foot Tracking Template Model Problem

Here are the socks model that I build. But when I import the fbx file into the foot tracking template, both models turn into the form of the right foot version.


I have tried to copy a left foot version and paste it to another Blender file to export it individually, but it still come out with a right foot version mesh when imported into the Lens Studio project. Is there any reason and solutions to this problem? It's so creepy and I really need some help on this issue. Thanks.

