Open Radar

 
Summary:
If an Apple Music track is downloaded to your iPhone to listen offline, but it has not been added to your iCloud Music Library, it is not possible in the iPhone app to add the track to your library without deleting the download first. When tapping the three-dots button, there is no option for "Add to Library", simply a "Remove Download" button, which turns into an "Add to Library" button when tapped.
It is still possible to add the track to your library on Apple Watch using the plus-in-a-circle button on the Now Playing glance.

Note that normally, it is not possible to have downloaded a track without having it in your library. However, certain apps which use the Apple Music APIs can add tracks to a playlist, _without adding them to your main library_. (For example, this Workflow script will do just that: https://workflow.is/workflows/74ca59c6a7cc4fd991c0c347cb405208)

If the "Automatic Downloads" option is enabled in Settings, and the "Add Playlist Songs" option is _disabled_, any tracks added by a 3rd party app will be downloaded but not added to your library. This issue will then arise where the phone thinks they're in your library when they're not.

Steps to Reproduce:
1. Enable Settings → Music → Automatic Downloads
2. Disable Settings → Music → Add Playlist Songs
3. Use a third party app to add some tracks to a playlist without adding them to your library (eg using https://workflow.is/workflows/74ca59c6a7cc4fd991c0c347cb405208)
3a. Wait for the tracks to download to your phone
4. Open the Music app and either 3D Touch that track, or press the three-dots button to open the menu
5. Attempt to add the track to your library, but fail because the option isn't there
6. Play one of the tracks from the playlist and open Now Playing on your Apple Watch, and note that the plus-in-a-circle is visible and does the correct thing
7. Return to iPhone, tap "Remove Download" on the track, then note that "Add to Library" appears in its place

Expected Results:
Both Apple Watch and iPhone should allow already-downloaded tracks to be added to your iCloud Music Library.

Actual Results:
Only Apple Watch allows this, and on iPhone, tracks must be deleted and redownloaded.

Version:
iOS 10.2 (14C92), watchOS 3.1.1 (14S883)

Notes:


Configuration:
iPhone 7, Apple Watch "Series 0" 42mm