Nextcloud on UCS 5.2.6: After upgrade from 32.0.6 to 32.0.12 (and now 32.0.13) existing ldap-users cannot login

Hallo,

during upgrade from 32.0.6 to 32.0.12 I encountered the problem with the user_saml app and the joinscript of nextcloud failing:

The difference is, that my system was already upgraded to UCS 5.2.6 and keycloak (not simplesamlphp!).

I fixed the join, but still have problems with existing ldap-users logging in to nextcloud. LDAP-setup seems basically Okay. I see existing and new users and groups in nextcloud. But only new users can login.

In the nextcloud-log I see the error message: “RuntimeException HMAC does not match.”

I have googled and tried to fix a lot, but did not find a solution.

Has someone an idea for me, how to fix that issue?

Best regards