enoch wrote:Is this VMware only or is it the same story with Hyper-V?
For VMware this happens, because a new restore point (snapshot) can no longer be mapped to the source disk, since it doesn't match the source any more. For Hyper-V, please see this topic for more info > Resize vhdx
enoch wrote:What if we reseize the VMware VM, then make a backup in Veeam and then replicate with the source set to Backup Repository instead of directly, will this also delete all the snapshot on the destination?
Yes, because snapshot should always "match the size" of the source virtual disk, otherwise there might be issues with snapshot commit operation.