I loaded a save where I never been at Luculla, talked to Brandon and quit.

The original state of LUC_Brandon_Plan is "AD 1C" and LUC_Brandon_Bothered is absent, but that does not help.

LUC_Brandon_Bothered ... 00 _6C_ 1D 00 00 0A (subtract 1 from 6D)
LUC_Brandon_Plan ... 00 _00_ 1D 00 00 0A (set to 00)

And the dialogue option is there again.