Some entries in iTunes just don't want to cooperate
I am reorganizing my music within iTunes, editing songs and groups of songs within the Get Info dialog box. By default, iTunes wants to separate the work of a particular artist into separate albums because of things like multiple artists. That and most other things I can deal with but there must be something else that iTunes uses for organizing songs that is invisible to me. For example, if I have a number of individual songs from one artist that all come from different albums and I want to gather them all together into one album, I know how to do that; or at least I thought I did. Some entries seem to want to resist being grouped together. I have gone so far as to write down every single selection, text (including capitalization and spaces) or any other parameter on every last item in every tab and double and triple checked to ensure everything except the song titles and track numbers was exactly the same. iTunes still will not combine the songs into one album. When I say I am matching stuff I mean I synchronize absolutely everything from the artwork to the file locations, the year, the compilations tick-box, the sorting, everything. If it is something that can be changed from within the Get Info dialog box I have synchronized it. I have left no stone unturned. Whatever it is that is preventing these entries from being grouped together has to be something outside of the parameters that can be set from within Get Info.
Any help on this weirdness will be appreciated.
iTunes 12.6.2.20
macOS 10.13.6