pvscsi "reset to device" errors during backups on vSphere 5

[ddockter]

Since upgrading to ESX 5 a week ago, I'm seeing quite a few pvscsi "reset to device" errors during backups. This does not happen to the VM being backed up, but to other VMs that are on the same NFS datastore. The errors come in bunches. So typically I will see it for multiple VMs at around the same time. This happened very infrequently when on ESX 4.1. Has anyone else experienced this?