error 5121 in clusterlog while backing csv volume with hardware vss writer snapshot

Hi.

we are testing backing up csv volumes with dpm using hp hardware vss writers. when i backup the environment i see that the volumes are in redirect io while the snapshots are being generated and then brought online and after that the actual backup runs from the snapshots but i still get alot of error 5121 in the clusterlog should i still have these while using hardware snapshots? the disk is of course in rederict io mode during the snapshot phase so i guess it should be like that but it shouldnt be flaged as an error in that case?