Assume that you use Microsoft SQL Server 2012 or 2014 Always On Availability Groups. After statistics are updated by using the FULLSCAN option on the primary replica, the statistics on the secondary replica become stale or out-of-date. When you run a query on the secondary replica, a bad query plan might be used. This causes slow queries.
Cumulative Update Information for SQL Server:
This issue is fixed in the following cumulative updates for SQL Server:
Service Pack Information for SQL Server 2012:
This issue is fixed in the following service pack for SQL Server:
For more information about how to obtain the latest service pack, see How to obtain the latest service pack for SQL Server 2012
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.