I think I am on the latest firmware. I am supposed to be on the latest firmware if I flash Global fastboot ROM? I have tried flashing the firmware zip before flashing the ROM in twrp. Nothing changed. What can be causing the lockscreen bug? It seems to me that some kind of lock screen setting are corrupted during flashing, causing the setting to crash. And what is even worse it doesn't work on different android versions so it is not version dependant.
So it seems that you're on latest firmware. It's not that important but somewhat an all around fix for Kate/kenzo.
I've no clue, I'm completely at a loss. Are you following current procedure?
1. Wipe dalvik/art cache, system, data and cache.
2. Flash rom, gapps, magisk and whatever you want.
3. Wipe caches after flash and boot.
If you're following that procedure try to just flash the rom and nothing else and report back your results.