Dragon Age Origins and Dragon Age 2 Alistair (spoilers)

Alright, ill start off with my choices in DAO. This playthrough (combined with what happened in DA2) puzzled my mind.

I think for the first time ever i didn't take alistair with me to the Archdemon, i took with me Morrigan, Zevran and Leliana, so he's left to defend the gate. When you kill the archdemon (i did the dark ritual with morrigan and gave the throne to Anora) and Queen Anora speaks to you in the throne room alistair isn't there. And she also says we should honor those who were fallen in battle and she specifically mentions alistair as well. As he is not in the room and we should honor him, he must be dead right?

Well i could live with that. Except now that i'm playing DA2 with that imported save file.

End of Act 2, the Qunari invade Kirkwall you come across a group of Grey Wardens. And suddenly, Alistair is there.

He doesn't mention anything from the blight in Ferelden so we can't make up anything from that.

Here is the codex entry i received after meeting him:

It says he's credited alongside the Hero of Feleden.

Did i just encounter a bug in DA:O where Alistair was supposed to be with me? Or did the save file from DA:O to DA:2 simply not include this?

The latter would seem really bad on biowares part.