Aha, I think the problem is that older versions of my package (including the one currently in Extras) had a broken bugtracker field (due to a bug in py2deb), and the testers are getting confused.

If you look at the package overview pages of my two projects, here and here, you will see that the bugtracker link is the link from the Extras package, not from the Extras-testing package.

It must be made clear to testers that they are looking at the fields on the package instance page, not the overview page.

Weirdly, the download pages on maemo.org (where my packages are 2nd and 3rd most popular right now ) have the proper bugtracker field from the Extras-testing version. There's definitely some inconsistency there.