slapd (Symas 2.6.1) does not start with syncprov

Migrating to new ldap server and getting problems. OS: Rocky Linux 8 (== RHEL/CentOS 8). Fully updated. LDAP software: symas-openldap-servers-2.6.1-2.el8.x86_64 cn=config and and data import (via ldif) on master. Everything look good. start/stop/restart is working. ldap access is working. Adding "syncprov" on master (to enable producer/consumer mode). Now the slapd on the master/producer crashes on start! Apr 26 18:31:27 apollo11 systemd[1]: Started Symas OpenLDAP Server Daemon. Apr 26 18:31:27 apollo11 kernel: traps: slapd[1379] general protection fault ip:7fa53a499f38 sp:7fa4f8e3d1b0 error:0 in back_mdb.so.2.0.200[7fa53a471000+40000] Apr 26 18:31:27 apollo11 systemd[1]: Started Process Core Dump (PID 1380/UID 0). Apr 26 18:31:27 apollo11 systemd-coredump[1381]: Resource limits disable core dumping for process 1377 (slapd). Apr 26 18:31:27 apollo11 systemd-coredump[1381]: Process 1377 (slapd) of user 0 dumped core. Apr 26 18:31:27 apollo11 systemd[1]: symas-openldap-servers.service: Main process exited, code=killed, status=11/SEGV Apr 26 18:31:27 apollo11 systemd[1]: symas-openldap-servers.service: Failed with result 'signal'. Apr 26 18:31:27 apollo11 systemd[1]: systemd-coredump(a)3-1380-0.service: Succeeded. The syncprov ldif dn: cn=module{0},cn=config changetype: modify add: olcModuleLoad olcModuleLoad: syncprov.la dn: olcOverlay=syncprov,olcDatabase={1}mdb,cn=config changetype: add objectClass: olcOverlayConfig objectClass: olcSyncProvConfig olcOverlay: syncprov olcSpCheckpoint: 100 10 olcSpSessionlog: 100 dn: olcDatabase={1}mdb,cn=config changetype: modify add: olcDbIndex olcDbIndex: entryCSN,entryUUID eq Magnus Morén