They brighten up only when activated, seems like, which is brief, I think they should always be bright when the ability is available. Tooltips would help, too.

I'm not getting the error with them not being lit up but I am missing tooltips.

That may be another legacy issue that the profile reset will fix, I'll follow up once I have a chance to figure out if the buttons are still greyed out for me or not.

I'm experiencing this as well. The buttons are grayed out, as though they are unavailable(although clicking them DOES work if prerequisites for the ability are met; just no visual indication whether it will work or not), and mousing over either button offers no tooltips to explain what they do. I only installed the addon maybe... two or three weeks ago? It was after patch 8.0 dropped, anyways, so I couldn't say whether this doesn't happen with a fresh install, or whether my install is still old enough to warrant a complete reinstall.

Is this fixed now?

Not for the ExtraActionBar(Button?) as of 35a, still greyed out and no tooltip, haven't had a ZAB yet to try.