Please disregard; this was made in error due to a number of factors. Mods, please delete.
Okay, so apparently the November 27th update which added the new (old) Omega Expedition affected the file structure; AMUMSS reports an Invalid Data Exception to a whole bunch of files, not limited to:
METADATA\GAMESTATE\DEFAULTINVENTORYBALANCE.MBIN
METADATA\GAMESTATE\DEFAULTINVENTORYBALANCESURVIVAL.MBIN
METADATA\GAMESTATE\DIFFICULTYCONFIG.MBIN
METADATA\SIMULATION\MISSIONS\TABLES\MULTIPLAYERMISSIONTABLE.MBIN
METADATA\SIMULATION\MISSIONS\TABLES\NPCMISSIONTABLE.MBIN
METADATA\SIMULATION\MISSIONS\TABLES\PIRATEMISSIONTABLE.MBIN
METADATA\REALITY\TABLES\EXPEDITIONREWARDTABLE.MBIN
METADATA\REALITY\TABLES\NMS_DIALOG_GCALIENPUZZLETABLE.MBIN
METADATA\REALITY\TABLES\REWARDTABLE.MBIN
METADATA\REALITY\TABLES\INVENTORYTABLE.MBIN
METADATA\REALITY\TABLES\PURCHASEABLESPECIALS.MBIN
MODELS\PLANETS\BIOMES\COMMON\BUILDINGS\PARTS\BUILDABLEPARTS\TECH\ANTIMATTERHARVESTER\ENTITIES\ANTIMATTERHARVESTER.ENTITY.MBIN
GCFLEETGLOBALS.GLOBAL.MBIN
GCGAMEPLAYGLOBALS.GLOBAL.MBIN
GCSETTLEMENTGLOBALS.MBIN
According to the news on Steam, the Expeditions will be switched around again on December 11th, December 25th, January 8th, January 22nd, and February 5th. I don't know how much of an impact this will have for external mods, but be forewarned.