If you can, post your Load Order?
I know you only have a few additions, but perhaps one is out of place?
Also, I'm not 100%, but I had something like that happen after I installed two versions of a mod I used often simultaneously.
Maybe this is the case with UOP or one of it's children patches?
Oblivion.esm
DLCShiveringIsles.esp
Unofficial Oblivion Patch.esp
UOP Vampire Aging & Face Fix.esp
Unofficial Shivering Isles Patch.esp
Knights.esp
Oblivion Citadel Door Fix.esp
as of now, i have deactivated SKIP...
I also use OBSE 18. OH and also have DarNified UI 132 as OMOD, just like the UOP and SI Patch).