Have a nice trip!
Regarding the issue, I'm not sure but it might have something to with MP3 conversion presets. Having "track gain mp3 conversion preset" auto-applied, even copying and pasting a single MP3 file sometimes freezes MB without leaving any error log. I remember I had the same freezing issues when I tried to convert RG values to SC values with that preset. So maybe it's not about auto-applying but about the preset. When you have time, have a close look at those mp3 conversion presets.