Prerequisite:

• match some files using the lookup or scan process.
• two files are associated to the same track in one release.
• the media-optical-modified.png icon is displayed (a CD icon + star glyph on the top right, in order to signify that some tag pending value changes need to be saved on those files).

Then to trigger the bug:

• Save that release (Ctrl+S)
• the media-optical-modified.png icon is still displayed instead of a media-optical.png icon!

Workaround:

• refresh the release (Ctrl+R)
• the media-optical-modified.png icon is now replaced by a media-optical.png