Sort artists grayed out
Numerous albums have songs in which sort artists and sort album artists entries are grayed out in the iTunes main window and in the Get Info fields. Filling in the fields gives black text until the Get Info window is closed: the item text turns gray immediately. Sort (song) name is grayed out in the Get Info window but is black in the iTunes main window. This behavior is bizarre. I can find no logic about which albums and which fields are affected.
Deleting and replacing a song does not eliminate the grayed-out fields.
The songs play, and the sorting is correct. They gray text is annoying, and I worry that this is a sign that worse problems may occur.
Mac Pro, OS X El Capitan (10.11.6), Mac Pro Early 2009