@Stephan:
Could you provide the output of the following command run on the system where the ldap failure happens:
dpkg-query -W -f='${Package} ${Version} ${Source} ${Status}\n' | egrep 'slapd|ldap|gnutls'
@Stephan:
Could you provide the output of the following command run on the system where the ldap failure happens:
dpkg-query -W -f='${Package} ${Version} ${Source} ${Status}\n' | egrep 'slapd|ldap|gnutls'