INS in-flight update: Should the "insert" light illuminate after beginning to enter a latitude?

Unlike during position and waypoint entry, beginning to enter coordinates when in HOLD mode on the INS does NOT cause "insert" to illuminate.

Also, after entering coordinates for latitude and pressing insert anyway, the value reverts to the previous position UNTIL longitude is also inserted. Then the position updates.

I do not have any evidence of what should happen here, but that feels inconsistent with other modes of operation, and therefore potentially wrong.