How to reproduce:
1. Open the attached project
2. Play locomotion_test scene
3. Notice that fishman_old file is on the spot, while the new file moves forward
4. Right mouse click on fishman_old.fbx file and select Show in Explorer
5. Go to New folder , copy fishman_new.fbx and paste to Assets folder
6. Go back to Unity
7. Drag fishman_new.fbx from Assets(the one you pasted) folder to the scene
8. Add Animator Controller fishman_new and play the scene
9. Notice that this model stays on spot

Notes: if .fbx is duplicated in Unity from New folder to Assets folder and 7-8 steps are repeated, the model will move forward.

The bug is caused by leftover Legacy Animation parameter "Add Loop Frame".
A workaround is to switchback to Legacy, uncheck the option, Apply and switch back to Generic.