Refactored to just include essential info on this problem - not a Mozilla bug. -- RichardDonkin - 29 Sep 2001
View the pre-refactored page here (opens a new window).

Symptoms

I just had an odd problem with http://twiki.org/cgi-bin/view/Main/ - using Mozilla build 2001071803, I had the TWiki logo image in the body of the page fail to load. On inspecting the source of the page, I found that the URL to the image was http://twiki.orghttp/cgi-bin/view/Main - definitely had two http: parts though my clipboard history wasn't on so I haven't got this exactly.

UPDATE: Just had this problem again on hitting Preview on this page, with same browser - I got http://twiki.orghttp/cgi-bin/preview/Codev/TwikiOrgImageProblem as the URL. On inspecting this page, I saw the following HTML:

<base href="http://twiki.orghttp:/cgi-bin/view/Codev/TwikiOrgImageProblem"> <meta NAME="ROBOTS" CONTENT ...>

This bug is intermittent - I retried editing this page with Mozilla and one time it gave the same problem, the other time it worked OK. Consistently corrupts the base href and other instances of http://twiki.org/ - never corrupts any other parts of the page

Diagnosis

This is not a Mozilla bug, it's a bug in JunkBuster (an ad-filtering proxy that I use), which doesn't properly implement the HTTP/1.1 protocol for proxies, at least in some versions. This problem appears because of changes in Mozilla 0.9.3 or later.

Workaround

From MozillaBug:38488 - you just have to go to Edit | Preferences | Debug in Mozilla, and set HTTP version to 1.0. You shouldn't need to disable keepalives but this was mentioned in the Mozilla bug report.

See BrowserIssues for a summary of this and other issues.