I also have this this bug, in my case i had dialogue options with kreia, but after installing unofficial patch 1.0c to a different folder than TSL is installed, these options disappeared. Apparently it messed with my files anyway. I deleted whole kotor folder, and installed everything form scratch. Without 1.0c. Still, have this problem. I even started new playthrough, but that did not help either.
After finding missing dialogue in kotor dialog editor I noticed 2 conditionals:
c_global_eq 000_Kreia_Nature
c_area 003EBO (or smth like that, cant check at the moment)
The dialogue in question is: "Kreia, what are you - are you a Jedi, a Sith?"
I remember asking this question in my first playthrough of TSLRCM 1.8, after whole this mess with 1.0c the dialogue is missing.
Is it possible that this patch messed with other files outside of kotor main folder?
[EDIT] fixed variables names and dialogue line