Did you use an older version of the OSOT to optimize your image? Prior versions last year and even some early this year were known to break the start menu I believe with either the some of the services that it disables or the way it tries to optimize/clear the default start menu.
I can't recall exactly what, but I will try to go through my notes to see what I unchecked to fix the issue
what Windows 10 Version do you use? I had this odd issures a while back and it was because I was roaming the tile database folder. I've blogged about this issue a while ago (https://www.vcloudnine.de/roaming-of-appdatalocal-breaks-windows-10-start-menu/ ).Best regards