In a plugin, let's say I download the page 'http://www.apage.com/path' using xmlws. If this page does a redirection to path '/redirect', Picard will attempt to load page '/redirect' instead of 'http://www.apage.com/redirect'.
I can reproduce this with any page on anidb.net that does a redirection.
To fix it, I added the following monkeypatch to my script (all pages have the string 'animedb.pl' in the path, so I use that to detect this bug).
Of course, fixing this directly on the xmlws redirect handler would be better.