Hi there. Thanks for posting.
I am interested in this as well. I experience this occasionally and, although unable to explain what it is or how/why it happens, what works for me is a simple exit from the VR session (MSFS remains open) and re-entry into the session and the white band typically goes away. If that fails to work I restart the headset (again MSFS remains open) and reconnect to the oculus app and then re-enter the VR session in MSFS.
Sorry I could not offer the technology behind what is happening but this forum is filled with impressively intelligent and experienced members, and looking forward to their responses.
Again thanks posting.