Disappearing archived articles

I've noticed that some articles on the main page don't show in the archives; is this a glitch or is it intentional. Here are a few examples:

http://www.theverge.com/2012/2/2/2765923/dance-dance-revolution-classroom-edition-48-players

http://www.theverge.com/2012/2/2/2765802/tworse-key-morse-code-twitter

http://www.theverge.com/2012/2/13/2795371/ti-wilink-8-integrated-nfc-glonass

http://www.theverge.com/2012/2/13/2795535/leaked-images-nokia-c3-302