Attendant console fails to show the status of a line correctly(it doesn't change at all) when a call comes from PSTN. This line is in a ringing line group. The line status show correctly when an ext. to an ext. call is made from this line. However, the line status correctly shows when the call from PSTN is made to a DID extension. Does this have anything to do with a fact that the ext. belongs to a line group?