Zone 0 is just what shows on the operator end when the panel itself is the subject. The Tamper alert is for the panel. This means that the panel’s internal tamper switch is not fully pressed in.
Often this occurs on a GC3 when the back plate is not screwed shut or if the battery cable is not inserted in the gap for it before closing the panel. It can put outward pressure on the plate and cause intermittent tampers.