NAV engaged on ground - A320
I had an aircraft where NAV indicated engaged while at the gate. We cycled the FD's. NAV then indicated armed but then immediately indicated engaged. We cycled the NAV data base dumping the FMGC and reinserted the flight plan. After reinserting the flight plan, NAV once again indicated engaged. At that point I was ready to dump the IR's and re align. It just so happened at that time the ground staff wanted external power disconnected. We did so and the power interruption/switch over fixed the NAV engaged problem and the FMA's indicated properly.
What was the reason for this anomaly?