[Brian]

Bushford, sorry for the confusion here! Both available and unavailable actions can end up in the overdue state. It sounds like your actions are overdue, but are not available.

If you select View -> Availability Filter -> Remaining do the actions in question appear?

Off the top of my head, I'm guessing those actions are part of a sequential project. Each step only becomes available once the previous steps have been completed. (Another possibility would be that they've been assigned to an on-hold context or project.)

Does that help?