The same Journal oddities were found.
I started DLC with my 20 lvl character just before choosing the side and going to Ukaizo, and I had this last Gods meeting on the way to the isle. Don't know if that had any influence, but when I killed the dragon nothing happend, cutscene didn'd start and all the NPC were barking the same thing about the dragon coming. So I had to start DLC anew.
I loaded the 17 lvl save before Hasongo and found that DLC entry are already inside the journal. This time everything was OK, I slayed the dragon and finally had that cutscene about finding Vatnir.
Then I decided to load my earliest save of this character to check if Journal entry keeps bugging. So yes, I still have all the entries dated by Foniverno 2824, but wait, it's Fonprima 2823 out there.