<!–more–> broken on archive pages in 1.5

The <!–more–> embedded in a post works on my front page, but not on a category/date archive page. The whole post shows, down to the “…” (wherever that comes from?).

Aside from not functioning as advertised, the rest of the post (which isn’t supposed to be displaying) has the html tags removed. Most notably my links don’t work, but I tried throwing in a bold which was also stripped.