Welcome to the forum, @brewick. If you make sure signposts are visible by switching off View > Signposts > Hide Signposts, do you see any signposts appearing anywhere in the percussion staves? My guess is that you have some hidden time signatures somewhere specific to the percussion staves that are causing the barlines to be hidden.
It will be easier for us to diagnose if you can attach your project here. Please see this thread: