Truly not surprised. It actually could be 100% your phone and 0%
MDE. I know that's really hard to believe seeing how wonky MDE is. If this is a case of your the only one with your exact error situation it really may be a situation with your phone and that's a case where they can't fix it. May be a combo of app and settings on your phone that they can not ever replicate. An app that you'd never even think of may be interfering
This whole going to the phone to replace the MB is never going to work for that reason. There are just too many things that can go wrong and too many phone and phone settings to ever figure them all out