I don't know how long you have been watching the show,(I started in January)but trust me, you will notice a lot of things like that. For the most part the people on the board call it "a lack of continuity". I've tossed the phrase around a time or two myself though I like to classify it as Plateau flower induced amnesia. Whatever this mysterious and baffling condition is, it has managed to reach epidemic proportions on our immense plateau.

Only in the more recent episodes do we see any teenie tiny baby steps towards continuity - references to past happenings/episodes: Roxton's brother accidental murder thing by Margie in "Chosen One" and in the same episode, Malone's remark asking Veronica could she blame the leech woman for wanting a child? (a reference to Time after Time ape baby incident) then again in Barbarians at the Gate (yet to be shown non Direct TV in the US) involvement of their first enemy Tribune and the stolen gun powder recipe.

We're all of course crossing our fingers that the writer's can find an antidote to the amnesia flower next season and get their act together....literally. (grin)