SDK issue on iTunes 12.6

Is anyone aware of a long-standing issue with the SDK on iTunes 12.6 ? There were no problems with 12.5.

One specific error is that on calling iTunesLib.IITTrackCollection.get_ItemByPersistentID it is throwing an exception with message "The playlist has been deleted".

Without knowing what the code is doing it is hard to guess what the cause of the error might be. There are some lists that iTunes doesn't like to share properly. IIRC Tones is one for some unfathomable reason.