Still having the issue on a P6P where when the AOD is enabled and goes into "standby mode" (i.e. when you lock the device and wait about 5 seconds, you see the screen flicker for a second and the AOD display goes into what I assume is 10Hz mode), the fingerprint unlock fails 100% of the time when the device is in this state.
It will pop a message saying "Press firmly on the sensor", followed by "fingerprint not recognized". Subsequent unlock attempts after this "failure" work 100% of the time.
I have tried re-enrolling fingerprints (remove all + re-add), messing with various security mechanisms (PIN scramble, auto reboot, etc), nothing seems to fix it.
Ideal behavior is the device will register the fingerprint normally, even when in lower refresh rate standby state. It used to work this way on stock OS, and on previous GrapheneOS versions based off Android 13. It was one of the latter A13 updates that caused this to start happening (for me at least), and has proceeded into A14 versions.