A 12.7 MB restore point from 6.1TB Data looks like an incremental to me.
The incremental backup has worked. You would have a 5TB Full Backup File, if incremental would not have worked. Read does not mean stored on the backup repository.
When all the disk content was reread, either CBT or File Tracking didn't work or reset somehow.
Do you use a File Level Backup Job or Volume Level Job to backup the disk?
There are two types of Change Block Tracking available for Volume Level Backup with the Veeam Agent:
- Default CBT mechanism
- Veeam CBT Driver
The default works only when protecting NTFS File Systems and the Veeam CBT driver, which would also work for reFS, requires a Veeam Agent for Windows Server license.
You use the free Agent and Drive E is reFS formated. So in your case, Veeam will always need to read the entire disk content and cannot use CBT. The Backup File will be increment, but all blocks from the production drive needs to be read to find changed blocks.