Just a head up, our QC has found another issue with this update. This second issue is completely unrelated to the previous one, and has to deal with Windows 2008 and earlier VMs.
Quick summary of all known issues so far:
1. Backing up Windows 2008R2 and later VMs on Hyper-V 2012 R2 hosts fails after update. Hotfix for this issue is already available from Veeam support.
2. Restoring Windows 2008 and earlier backups made on updated Hyper-V 2012 R2 hosts fails. No solution at the moment (my contact at Microsoft has just confirmed the issue present).
I will keep providing updates on the situation in this topic. You can subscribe to notifications by clicking the link at the bottom left of this page.