IBM Model M - Caps as Option treated as a toggle?

I've got my PS/2 Model M working with the Voodoo PS/2 kext in Sierra.

I'm trying to use the Caps Lock key as "Option", because there is no physical windows/meta/option key on this keyboard. But there is an issue, caps is still treated as a TOGGLE, instead of a normal key.

So the first time pressing caps after a reboot, it's as though option is being held down. Anything i type from then on is weird characters like åˆø¨∂ßøˆ∆∑´ƒ˚∆¬˚, which I understand is a default behavior of osx when holding option and typing.

Unplugging and replugging the keyboard doesn't solve it, I am forced to reboot.

Caps as option works as expected on my USB steelseries keyboard.

Other hardware in case it's relevant: 3930k, Asus Sabertoothx 79.

Is anyone using a Model M with Sierra and have this working succesfully? Any other ideas?