Assume that you perform a transaction log backup on the Availability Replicas for an AlwaysOn availability group in SQL Server 2012 or 2014. If the backup fails on the secondary replica, a backup lock is held on the primary replica. Therefore, subsequent transaction log backups are also unsuccessful.
Update informationThis issue is fixed in the following cumulative updates of SQL Server:
Cumulative Update 1 for SQL Server 2014 SP2
Cumulative Update 4 for SQL Server 2012 Service Pack 3
Cumulative Update 8 for SQL Server 2014 SP1
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.