We have noticed that some of our users have a playlist or library that exceeds a safe operating size. In order to ensure the best possible performance for you and all of our subscribers, we have recently introduced a limit to the number of tracks that will display for a playlist or library.
This change will affect all the users who have a large number of tracks in their playlist or library with more than 10,000 tracks. Users will not lose any of the songs that were added to their playlist or library, but they may not have access to newly added tracks or some older tracks. This constraint on the display of tracks can be frustrating, but prevents adversely affecting the performance of our service for other users.
We are working on a fix. Stay tuned for updates. Thanks for your patience while we work to resolve the problem.