Database file is being used by another process

We are running an Exchange 2010 SP3 UR27 environment on Windows Server 2008 R2. I am aware that support for Exchange 2010 is ending soon, and we are planning to migrate to a newer platform before then. I am seeing issues with database files being in use by another process, when failing over to other Exchange Mailbox Servers which subsequently causes a crash of the Information Store.

We are running a DAG on 6 physical servers, with 4 copies of each database. The system is running fine on a daily basis, but when failing over databases to other servers, problems starts to occur. The Event Viewer reports:

mxexchangerepl (6860) An attempt to open the file "C:\ExchangeStorage\DiskX\DBX\DBX.edb" for read only access failed with system error 32 (0x00000020): "The process cannot access the file becaise it is being used by another process.". The open file operation will fail with error -1032 (0xfffffbf8).

There is no antivirus on the server or similar security software that scans files.

There aren't any connections to shares, other than other Exchange Database Servers in the DAG.

All databases have Circular Logging enabled and running daily backups through DPM, where we see problems with backups hanging.

Receive-Side Scaling State (RSS) and Chimney Offload State are both disabled.

Does anybody have any ideas what else could cause such issues?