Facial expressions not working

I recently attempted to headswap Fakefactory’s Gordon Freeman Model onto another body.
The model compiles fine, however face posing does not work, the face poser inside gmod shows all the usual sliders but they seem to do nothing.
Any ideas?
inb4 yes, I used the .qc from fakefactory’s decompiled model. And I do not intend to redistribute this, it is just for personal use.