Post your mod list; it could be MMM conflicting with something, but I've never, ever had that problem.
Well it's working w/out MMM enabled, here's the current list/load order -
Fallout3.esm
Anchorage.esm
ThePitt.esm
BrokenSteel.esm
PointLookout.esm
Zeta.esm
Unofficial Fallout 3 Patch.esm
StreetLights.esm
Unofficial Fallout 3 Patch - Operation Anchorage.esp
Unofficial Fallout 3 Patch - The Pitt.esp
Unofficial Fallout 3 Patch - Broken Steel.esp
Unofficial Fallout 3 Patch - Point Lookout.esp
Unofficial Fallout 3 Patch - Mothership Zeta.esp
SkillBookPerks.esp
DarNifiedUIF3.esp
StreetLights - Wasteland.esp
Fellout-pipboylight.esp
Bobblehead-NoBoost.esp
Fellout-Full.esp
megalight.esp
Edit: It's started again in Rivet City w/out MMM enabled. :[
Are my saves somehow getting corrupted maybe?