Apple - iTunes incorrently splitting the songs in an album. Metadata problem?

I've only ever seen this happen when the metadata absolutely differs in some way between tracks. There are two ideas that come to mind:

1. Highlight each individual character and make sure 3 dots ( ... ) haven't been transformed into a single character elipses ( … ). Highlight each of the dots above and you should understand the difference.

2. Check the 'Sorting' section too and make sure all of that data is identical, notably in the 'Grouping' fields.

I would suggest selecting all four songs and doing the following:

1. Delete metadata from the tracks: at least Grouping, Album, Artist, Sort Album, and Sort Artist, but more wouldn't hurt.
2. Save the absence of the data by selecting "Done."
3. While they continue to be selected, Get Info again and fill in the relevant information.

I've found that no matter how much some fields may look identical, resetting them to be identical together often solves the problem.

For all the tracks, selecting "Part of a Compilation" - "Yes" solved this one for me (though it was not part of a compilation, it was the only way I could get it to cooperate).

This works, due to the way iTunes organizes compilations. The likely problem is that some of the files incorrectly have a compilation tag in the metadata and iTunes is looking for the same tag in the rest of the files and - not finding it - is placing the files in separate albums. Use a metadata editor to open up the files and clear the tag from the offending files and re-add them to your iTunes library and it should be all grouped under one album.

I tested this by adding a compilation tag to two files out of an album and importing to iTunes and did indeed get the files split into two separate albums. Removing the tag fixed the problem and iTunes imported correctly.