Alright, back with some test results:
I started out with a set of files that gave me 3 tracks when importing. Changed the names to all files to “a.wav”, “b.wav” and so on. Got something like 6 tracks. Changed the names to 1a, 2b, 3c and so on, then it came out correctly on two tracks staggered. Changed the names to aa, bb, cc etc, same result with that.
Went back to the original files with the original names, imported all but one file to see which one was causing problems. In this case it was specifically one file called “Wolves of Ardeal.wav”. Excluding that file will stagger on two tracks. Renaming that file to something else, INCLUDING renaming it to “a.wav” will make the files stagger correctly. Changing the name back to “Wolves of Ardeal.wav”, back to the same behavior. Changing it to “Wolves of.wav”, works correctly. Changing it to “Wolves.wav”, works correctly. Changing it to “Ardeal.wav”, now I get 4 tracks.
Further experimentation:
“ar.wav” = 4 tracks
“rd.wav” = 2 tracks
“de.wav” = 2 tracks
“ea.wav” = 2 tracks
“al.wav” = 4 tracks
“at.wav” = 2 tracks
“el.wav” = 5 tracks
“et.wav” = 2 tracks
“e.wav” = 2 tracks
“r.wav” = 4 tracks (shoutout to Justin)
“er.wav” = 5 tracks
“erer.wav” = 5 tracks
Now, as fun as it is to spend the weekend experimenting with this, I think I’ll tend to something else for a bit. 
But I think we’ve narrowed it down to that the name is key. Also doesn’t seem to be the length of the name, but rather a combination of letters in the name, or specific letters.