Default Help UNROOT my G2 international

i have the international 802 version of the g2 and i followed this guide by the letter, trying to unroot my device
although the root checker says in not rooted and SU doesn't work, when i put my phone in download mode status ROOTED written in red appears.
i did a factory reset, i also tried to unroot it with kingo, but with the same result.
can anyone please advise me how to get rid of the status ROOTED and go back to normal?
thank you very much!

PS:
if the answer is already here, please point me to it, because i can't find it by myself
Lg G2 802 International 32Gb
ROM: Depending on the week day