When I flashed this kdz, I did not lose data. However, I did have FC's all over the place because of the customizations I had made while previously rooted. So, I ended up wiping with a factory reset anyway.
You could try just rooting again right after flashing and see what happens. I did not try that before just wiping. Either way, you should back up your data first.
Sent from my LG-D801 using XDA Free mobile app
LG G2 D801 on T-Mobile
ROM: Stock KK D80120e (rooted)
Kernel: Dorimanx v7.6
Recovery: TWRP v2.7.0