Quoting Niels Thykier <niels@thykier.net>:
The website suffers from an issue where it is not clear that (seemly) duplicate tags are actually "once per architecture". This is not limited to any particular tag and I suspect that is what you are seeing.
The lintians are also counted twice (but not more) on the tracker: https://tracker.debian.org/pkg/zeroinstall-injector (4 issues, should be 2) https://tracker.debian.org/pkg/389-dsgw (3 issues, should be 2) ... If it would be "once per arch" there were many more, not only twice?