That I don’t know… It has something to do with the generation of the conform/media cache files. We had a lot of (very long) .mts files with similar names (mostly 0000.mts). As soon as I imported new files, some of the old ones in the timeline started to act strange (as in ‘playing audio from other 0000.mts-files). Deleting all the 0000-cache files (.cfa and .pek) and letting the cache files regenerate solved this issue, for a while… Tried to play around with the import settings (generate .xmp-files), but this didn’t solve it either. Worked around it by “render and replace” the audio track, which generated a new audio file.