Fingerprint reader does not work (Kubuntu)

[snow]

On Kubuntu I enrolled my fingerprint normally with "fprind-enroll" command. Then I put the line:

"auth sufficient pam_fprintd.so" in the /etc/pam.d/polkit-1" file to test it. The login with finger print is not offered and does not work at all. I tried with "/etc/pam.d/sudo". The same result: no effect.

It seem to me that FP reader does not work generally in Kubuntu 20.04. Parallelly I test with Ubuntu 20.04. All things above work there. I use a brand new Lenovo Thinkpad T495 with finger print reader.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: fprintd 1.90.1-1
ProcVersionSignature: Ubuntu 5.4.0-21.25-generic 5.4.27
Uname: Linux 5.4.0-21-generic x86_64
ApportVersion: 2.20.11-0ubuntu26
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Mon Apr 13 12:36:32 2020
InstallationDate: Installed on 2020-04-02 (10 days ago)
InstallationMedia: Kubuntu 20.04 LTS "Focal Fossa" - Beta amd64 (20200401)
SourcePackage: fprintd
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[snow (mrauschert)]

Meanwhile I found out that to enable the FP reader in Kubuntu you have to add these lines to the common-auth file in pam.d folder:

# here are the per-package modules (the "Primary" block)
auth [success=1 default=ignore] pam_unix.so nullok_secure
auth [success=2 default=ignore] pam_fprintd.so max_tries=1 timeout=10
auth [success=1 default=ignore] pam_unix.so nullok_secure

With this it works, but one problem still exists. After a reboot the first login fails very often, you have to repead the login. Sometimes it works sometime not.
When you logged in once, and lock the computer then the unlocking with FP reader works fine. Also in oher situations.