>It isn't a "bug" exactly, but rather it's just the 
>program does not compare the file size difference 
when 
>it's working out whether the file needs updating or 
>re-downloading. I believe it uses the ETAG when 
working 

Well, the problem is in fact to detect the first time 
the connection break.

When updating, the engine just asks the server "Give 
me this file, except if the Etag was ..." or "Give me 
this file, except if it was not modified since this 
date: ...". The problem is that the engine can not 
check the remote size, except if another request is 
made. 

If you have a broken URL which isn't refreshed when 
updating, I'd be interested to make some tests. I 
strongly suspect the server NOT to give any 'Content-
length' field, and therefore the engine can only 
detect the enf of file when the connection is broken. 
The problem in this case is: you can not make the 
difference between a broken connection due to end of 
file, and a broken connection due to a network problem.