switchover_status is RESOLVABLE GAP but there are no gaps and redo is being applied

Our 12.1.0.2.0 physical standby database was down for about 5 days and after starting it back up it and after a few hours I checked the status. Everything appears to be caught up with redo applying and all archive redo logs transferred to the physical standby database. The following query shows a status of RESOLVABLE GAP (query is run on primary database):

select switchover_status from v$database;

There are no errors and no gaps anywhere except from the switchover status. I've tried restarting the redo apply services on the physical standby and switched log files various times. I'm not sure how to get from RESOLVABLE GAP to TO STANDBY.