Auto-sync with 'Level volume when synchronizing' checked writes REPLAYGAIN_TRACK_GAIN and REPLAYGAIN_TRACK_PEAK tags to the library files. This really crappy. MM should not be using my audio files to hold its own temporary data.
If anyone knows a workaround e.g. some INI setting to disable this, please do say.
EDIT(TC) Tracked at http://www.ventismedia.com/mantis/view.php?id=6813
1299 Levelling autosync writes tags to library files [6813]
Moderator: Gurus