I have the same problem as well. After encrypting a folder with a password and fingerprint, it will regularly request for the password to be entered again which can be inconvenient if you have a complex password and want to access encrypted files quickly. I noticed the problem will often occur after a reboot of the device.
I am using a ZTE Axon 7 with LineageOS 14.1 (Android 7.1.2)
I have the same problem as well. After encrypting a folder with a password and fingerprint, it will regularly request for the password to be entered again which can be inconvenient if you have a complex password and want to access encrypted files quickly. I noticed the problem will often occur after a reboot of the device.
I am using a ZTE Axon 7 with LineageOS 14.1 (Android 7.1.2)