Slitherine

This happen on Norway. I have all objectives except for Namsos, i am pushing north. But then game ends with a marginal win for me?
And i have 7 turns to go...

Decisive Victory: Capture all objectives with at least 9 turns remaining.
Marginal Victory: Capture all objectives except Namsos.
By capturing all the objectives before Namson and with less than 9 remaining turns, the game ends with Marginal Victory.
The devs wanted to vary the victory conditions with Norway.

It also turned out to be one of the more unpopular and very confusing ways to 'vary' a map (along with having less deploy zones than core size) so you'll likely not see many (if any) scenarios of this sort of design in the future.