Can't get back to 4.3 once you've upgraded your boot loader - which it appears you have done with x note 9. look at the TWRP thread and get the version for KK and it should work.
If by some reason your BL hasn't upgraded, then just flash a 4.3 rom.
Sent from my SM-N9005 using XDA Premium 4 mobile app
// LG G3 (D855) // Stock // Stock //
S3(White) > M7(Red) > Note 3(Black) > Nexus 5(Black) > M8(Gunmetal) > LG G3 (Titan Grey)