It sounds like you are suffering from a well-know bug in Windows Server 2012 when doing VSS snapshots of Cluster Shared Volumes. It bit us too, same exact behaviour. Here
is a thread on TechNet where the problem is discussed in-depth.
Anyway, you should install the hotfix
provided by Microsoft (Version 2), and see if it solves your problem. Be aware that disabling ODX might be required as well, as described in the hotfix page. After applying the hotfix and disabling ODX (for our Dell MD3260 SAN), we haven't had any incidents of either memory leaks or errors.
Microsoft warns however that not all the bugs in the CSV back-end are solved with the current hotfix, and that they will bring out further fixes.