I have it set to actually write this tag the file so I don't have to re-analyze all my music on each computer in the house. I have noticed in the last few builds this isn't being written, but it is still checked in the settings. If it helps, I am using FLAC files and 17.0.182 and files have already been analyzed. The information shows up in the tags within MC17 but it isn't actually written to the file.