Hi,
I am not an expert on the technicalities, and someone with more experience may be able to explain it better. However, I can confirm that there is no issue capturing and deploying Windows 11 with FOG 1.15. I capture and deploy Windows 11 weekly without any problems. I mainly use the Single Disk (Everything) option, but I have also used multi-partition successfully.
Based on your description, it sounds like your configuration is not capturing the boot partition. As a result, when the image finishes deploying, the system cannot find a valid boot mechanism and falls back to network boot.
I am not aware of any completion message on the server. As far as I know, once the progress bar in the Task tab reaches 100%, the image has been fully cloned to the computer. Can you confirm if that is what you are seeing?