The option "Save to file tags (when possible)" is grayed out in its definition. So it is not automatically written as a file tag and apparently is not written by "Library Tools > Update Tags (from Library)" either.
However you can create a custom tag which is writable to the file and set its value to "[Album Artist (auto)]" or equivalently the function "AlbumArtist()" using an Expression in the MC tag definition (omit quotes). Name the custom tag accordingly to match a tag which your other app reads. The name cannot be "Album Artist" or "Artist" since those are built-in predefined fields for which MC does not allow an expression definition. You might try "AlbumArtist" for example.
You can also enter the value manually in the file's tag entry field in left side pane using "=[Album Artist (auto)]" or "=AlbumArtist()". If desired, first select the album to apply to all tracks at once. Or define the custom field with "Relational: Store one value for each album".
Yes… JRemote manages both fields beautifully. Putting all multiple-artist albums into it’s own category, “(Multiple Artists)”, and listing album artists in the category, “Artists”. The few Android apps that read the AA tag, do it a bit differently… also creating 2 categories, Artist and Album Artist, but instead lists all artists under “Artist”.
I happen to be dealing with a Android player that I want to use because it’s integrated with the DAP, and while it does offer a “album artist” switch for importing, it still lists all artists under a single category, Artists. The switch does something because the import process takes
~50% longer, but I cannot figure what…