Yeah, they're smushing together a bunch of sequential events into one big pile and I don't really like it. Even though the novels are pretty ok at best, the characters, Lugh especially, remain consistent.
The flash-back was actually really good at portraying what was just a sentence in the novel, but cutting out that Lugh went to brothels to deal with his horniness and pulling back on what was supposed to be Dia and Lughs first intimate night is just lame.
Stories are about the journey, not the destination and the manga is taking a pretty weird route that I don't think is as good as the original.