It seems that the 400% Bonus Expedition Results Discoverer perk and the 9x DM Event are conflicting with each other.
My DM results between November 22 and December 1 were: (newer, larger fleets) 1568, 1396, 1312, 1532, 1584, 2252, 1200, 1236, 1544, 1428, 2576, 1396 (older, smaller fleets)
The DM result since the start of the 9x Event has been: 1252
I have more expeditions flying to see what I can find, but it should be pretty clear that one of the bonuses is not applying.