Why cant I Keyframe Soft Selection?

My Vertex Soft Selection isn’t able to keyframe changes to the mesh. Can someone tell me why? I honestly believe I’m at the point where people don’t know the answers. Yes, I tried googling this.

I can autokey soft selection changes, but I can’t manually do it.

It’s weird because I’m only able to keyframe changes to some models but not all.

I don’t know if this is gonna help for what you need but have you tried using the morpher modifier?

Yes, I do use it and it screws up with my Louis model. Everytime I try to keyfrme his facal expression he slides to the left or right for some reason.