Mediabay - can`t edit attributes in some files (origin time)

Hello !
I have a problem with the media bay - I cant seem to edit origin in some files (they are in red), even though I can in some other files. The location seems not to be important, tried copying files to different drives etc. Most of the files I export from Cubase CANT have its origin changed. I cant pinpoint what makes the editing impossible. Checked if they are read only, but no.