Error : Process ID attempted to unlock a resource it does not own: HOBT: 5:72057602511994880 keeps on appearing in logs every second

I am using sql server 2012.

Microsoft SQL Server 2012 (SP1) - 11.0.3393.0 (X64) 
Oct 25 2013 19:04:40 
Copyright (c) Microsoft Corporation
Standard Edition (64-bit) on Windows NT 6.2 <X64> (Build 9200: )

In log viewer i am getting 3 consecutive errors that keep on appearing every second:

Process ID 141 attempted to unlock a resource it does not own: HOBT: 5:72057602511994880 . Retry the transaction, because this error may be caused by a timing condition. If the problem persists, contact the database administrator.

Error: 1203, Severity: 20, State: 1.

Exception occurred in destructor of RowsetNewSS 0x000000051E2DC990. This error may indicate a problem related to releasing pre-allocated disk blocks used during bulk-insert operations. Restart the server to resolve this problem.

And it is causing sql to use high % of cpu and memory.

We did set maximum server memory 50 GB on a 60GB memory server.

What could be causing this error?