Buggy behavior of a particular download.

[grey-hame]

I have a 2.2 meg file downloading from a single source that has the whole file. It gets to 72 percent and then the following, mostly incorrect state transitions occur:

From "downloading" to "queued, 3 of 3".
From "queued, 3 of 3" to "pending".
From "pending" to "queued, 2 of 2".
From "queued, 2 of 2" to "pending".
From "pending" to "searching (no sources)".

This is pretty much exactly backwards. The correct sequence is searching, pending, queued, queue position decreasing, downloading, and then done.

Why would it start making backwards "progress" like that, and how do I jump-start it so that it works properly again and gets the rest of this particular file? Furthermore, how do I stop it from going backwards ever again, for any file?