Did anyone noticed Touch ID getting disabled or previously saved fingerprints are deleted, after installing the macOS 10.15.6 update ?
I installed the update last week and since then the Touch ID stopped working and I had to use password to login. After checking the Touch ID settings I find out the fingerprints are deleted. I added them back and now it's working fine.
I have few users reporting the same issue and for some of them the finger prints were not deleted, though they had to remove the saved fingerprints and add it back to make it work again.
sorry for my late response, I stumbled upon this thread by accident :-)
After updating from catalina 10.15.5 to 10.15.6 , I faced the same issue and more: The keychain was no more able to use.
Looking inside the user settings, I noticed, that using the keychain via apple cloud was disabled. I had to reactivate the hook and then the fingerprints were usable, again.