I was having this and I think it was because the scmp file was checked in to git and my git changes panel in VS showed it was in a borked state. VS may have been unable to check out the file to apply any updated metadata. I closed and reloaded my solution, added the schema compare file to my ignore list, and was able to see the differences.

I was having this and I think it was because the scmp file was checked in to git and my git changes panel in VS showed it was in a borked state. VS may have been unable to check out the file to apply any updated metadata. I closed and reloaded my solution, added the schema compare file to my ignore list, and was able to see the differences.