Tags pointing to Things don't go to the right URL

(Bug, Closed -> Fixed, Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Tag Sets
Summary: There is a deadly inconsistency between how Tags and Links are being URLified at the moment, and the result is that you can get inconsistent results, with a Tag pointing to what appears to be an undefined Tag page, but tweaking the URL reveals a real Thing.
For example, in the Respectful Calm Space, take the Plot "Incriminating Letter". If I go to the Thing itself, I go to this page. But I also have a Plots property, so that Archetypes and Characters can go to it, and those links to to this URL, which doesn't actually list the guts of the Thing!