Situation: When we are monitoring the recovery health of a replica and we are checking the recovery state we must use the is_local column to first determine if the replica is local. If the replica is not local it will return NULL as described in the referenced link. In short we are reporting an alarm when it is behaving as it is expected to. As a result there is nothing for the DBA or other support personnel to fix.
Reference: sys.dm_hadr_availability_replica_states (Transact-SQL)
Request: Take the is_local flag into account as described in the reference.