VHDX Hosted on Hyper-V SMB not using CBT

[DannieA]

We have two hosts. S00 is a Hyper-V Server with Veeam installed on the host. This machine has multiple VM's as well that are backed up by Veeam. We have a second Hyper-V host S03 with multiple VM's that are backed up to repositories on S00. Additionally this second host S03 has some spare storage that I present to a file server vm F01 on the host S00 using SMB (\\S03\SMBVHDX\) to mount the spare storage to the file server F01.

Issue is, when backups are performed on the VM F01, all the disks except for the SMB shared VHDX from S03 use CBT. The SMB shared VHDX has failed to use CBT.

It did use CBT a couple of times, and that was before I added jobs that pointed to VM's on S03 to Veeam I believe.

For clarity, S00 and S03 are both listed under Hyper-V and S03 is also listed under SMB as well. SMB VSS feature is also enabled on S03 as needed for shadow copies.

Tier 1 support tells me they are unable to replicate it, it works for them ok. I asked them to escalate the issue and he refuses to do so. He says he spoke with Tier 3 and they said it isn't supported. I've checked all documentation and I see no word of where it isn't supported or why it wouldn't be. Tier 1 appears to be under the impressions that SMB is a server role and pointed me to an article that showed that Hyper-V shouldn't have any other roles installed. I made him aware, Microsoft supports this configuration just fine, SMB isn't a role and in fact it is how Microsoft supports shared nothing migrations.

I can't imagine i'm the only one with this configuration, and their solution was unreasonable (to move the VM's to a new host?!). Additionally, he even admits he's unable to replicate my issue.

Anyone run into this before, and how do I get someone to escalate it to the next tier, I've lost confidence in this particular support personnel.