I have same issue.
Each time I need TWRP I just remove pin and fingerprint then add back once done in twrp
Running P DP1 and have latest twrp installed. Went to flash latest Flash kernel today, rebooted into recovery and twrp would not accep...
some devs have this working already and might be issued publicly soon
Or just flash the OTA file using the stock recovery and it won't wipe either.
I found doing that sometimes creates issues with system.
Best to flash new image with -w
OTA can take 2 weeks to be pushed to all devices
unlock oem bootloader in DEV options
if you want to keep all settings remove the -w in flash all