The carriers are a girl and her husband, and I became convinced that one or the other of them was leaving the paper at the wrong apartment. They were insistent, to the District Manager, that they were delivering the paper every day, and she obviously believed them, and when I proved to myself that no one was stealing the paper every couple of days, I decided that one of them was leaving the paper at the wrong building. These apartment buildings all look exactly alike and the apartments are all numbered 1 through 12. So, if one of the carriers left the paper at my apartment one day, and the other one left it at #9 of the building next door, the result would be that I would get my paper one or two days in a row and then not get it the next day or two.
I don't know for a fact that this is what happened, but it would explain why the paper was there sporadically. Anyway, I'm glad it's resolved, however it happened.
Now, I can concentrate on being irritated by Miss Potty Mouth next door and Drunk and Disorderly upstairs. At least, it'll be a change.