When I tried to add LKA I broke Forward Alert, AEB and host of other things. Reverting the changes did put it back to LDW for me.It seems that this change broke my LKA cameras. I have reverted the changes back but LDW is not working anymore. I'm getting yellow triangle Forward Alert Warning and LDW doesn't work.
I suspect that you may have left something else enabled that you need to set back.
You may also need to update your cameras through IPM A to get LKA to work.
Have you been meticulously noting which options you are changing or just clicking boxes in the hope you fix it?