I know this is old but for anyone having this problem, this is what fixed it for me.
Open the P_MissionH01.txi file from this download in notepad and add these lines under envmaptexture CM_SpecMap:
mipmap 0
downsamplemax 0
clamp 1
For me, Mission was the only one showing the black line and only during gameplay and not cutscenes or her character profile. If this doesn't work, there's more stuff you can try in this thread: Black Line in middle of face. - Page 2 - General Kotor/TSL Modding - Deadly Stream