This is the attendant console setup with the first available member algorithm.
Hunt group members:-
User 1 line 1 User 2 line 1 User 3 line 1
If User 2 logs in first, and then the User 1 logs in, the hunting starts with User 2 and then goes to User 1. Although in the hunt group, User 1 is the first that has to be checked, CallManager is apparently completing the order in which the users log.
In case the second User (User 2) goes offline and the call gets routed to User 1 and then User2 logs back in, calls start to route properly as configured in Hunt group.
In order to resolve the issue, restart the Telephony Call Dispatcher (TCD) and computer telephony integration (CTI) services. If the issue remains the same, reset the Pilot Point and this ideally fixes the issue.