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
You try it yet on beta 2? I have been thinking about it!
I have not as of yet,
going to clean flash this weekend and test
Well now I need to flash beta 2. Lol