Well, i have Ascension and Redemption installed, but Irenicus has his normal conversation at the beginning of game and outside his dungeon, but shouldn't he has a new dialogue?

try to re-install, and i don't know the mod myself

or else, could it be a patch problem?

iirc ascention and redemption only start to kick in nearing the end of Tob. I can't remember whether the beginning game dialogues were altered at all.

Ascension and Redemption are ToB mods, yes.