Personally I think he just wants to write without consulting his notes most of the time, especially since even he seems to forget events or lore stuff that happened in the past (i.e. a lot of stuff that happened in OIAL except for bits and pieces plus the harem ending, Nuhrein being introduced as the language of Eternum but never popped up anywhere prior to the initial intro, forgetting about the fox ladies in 0.3*, forgetting how the Amulet of Blair works**), possibly due to focusing too much on his work and only the major bullet points and forgetting the little things.
And tbh, I wouldn't blame him if that was the case. OIAL's events are basically such an isolated incident that you can get away with not referencing much of what happened there. But something as monumental as the aftermath of Eternum would require you to be more aware of what went down and write about what comes after/how the world survived (or not and just set it in a post-apocalyptic worst case scenario), which for a dev who prolly wants to write mostly self-contained stories that don't require you to read earlier stuff is something that could be quite the bother.
*No joke, this was a convo back when 0.3 was still the latest update