link to same project for "report another bug"

Yes, it was because you had just added an upstream bug link. Doing that made Launchpad switch into the upstream X-Chat context, which made the "Report another bug" link point at upstream X-Chat instead of Ubuntu's xchat package.

So the simplest fix for this problem is for Launchpad *not* to switch contexts like that when you add an upstream bug link, in which case this is a duplicate of bug 72981. Does that seem reasonable? (There are other ways this problem could be fixed, such as having a separate "Report another bug" link for every project and package referred to in the bug report, but that would be more cluttersome.)

Context switching is bad. :) Here are a few options that would make sense, but most are full of clutter...

(1) add a new icon to the summary table at the top that allows you to report a bug for the right project;
(2) "report another bug" takes you to an intermediate screen that lets you choose which of the related projects you want to report the bug about;
(3) choose from a drop down list of all projects listed in the summary table;
(4) Is the yellow bar always the original bug? and the white ones are "also affects project"? Leave the link as relating to the yellow bar. In my mind "also affects project" should never be more important on this page as the "yellow" bar.

I should clarify #3: The link at the bottom of the page would be replaced with a drop down menu of available projects to tie the new bug report to.

Of course if you prefer the #4 option this bug should be marked as a duplicate of bug 72981.

The "Report another bug" link already does apply to the software highlighted in yellow, because the yellow bar shows (or aims to show) what context you're in. For example, compare where the link goes on these pages:
<https://bugs.staging.launchpad.net/rosetta/+bug/3>
<https://bugs.staging.launchpad.net/ubuntu/+bug/3>
<https://bugs.staging.launchpad.net/ubuntu/+source/mono/+bug/3>

All other things being equal, a fix that doesn't make the interface more complex is better than one that does. So since fixing bug 72981 would have solved your problem without adding any extra elements, I'll go ahead and mark it as a duplicate. Thanks for the report.

Perfect, thanks!