Liquid Damage, Keyboard Trackpad only work "option" key selections?

I find this a little weird so I was hoping someone could shed some light.

After my macbook pro had liquid damage the keyboard and trackpad will not work when the computer boots into it's primary or recovery partitions.

They will work, however, when holding down the option key and having my boot options come up. After I select a boot partition they no longer work.

USB keyboard and mouse do work when booted.

Any insight??? I know my way around but this doesn't make sense to me.