When upstreams delete tags portscout doesn't delete them and then shows them forever.
* misc/nn-insight (my upstream): I made a mistake and created a wrong tag 9d95926 that I later deleted. Yet, portscout still shows it.
* devel/xeus: portscout shows 0.23.15 when the latest tag on GitHub is 0.23.14 They likely created and deleted the tag, but portscout picked it up while it was there and now still has it.
For each port, when a new set of tags is harvested old tags should be removed from the database before saving a new set of tags. It seems like portscout just inserts new tags and keeps all old tags in the database which leads to the erroneous behavior.
Now there is one more: dns/coredns
These appear because of somebody's mistake, and then never disappear when these mistakes are fixed.