I'm getting same error - did you solve this problem ? if yes what was the solutioni currently have the following problem. when i use the synchronize button under user management > ldap > the following error always occurs:
Can't kill a non-numeric process ID at /usr/share/perl5/LockFile/Simple.pm line 584. (500)
The error occurred at 16:24:00 - 16:24:20 but no message is logged in journalctl -f. I've created a new LDAP-Sync with exactly the same configuration and it works. But I'm not able to delete the "buggy-sync" because of the same error "Can't kill a non-numeric process ID at /usr/share/perl5/LockFile/Simple.pm line 584. (500)"please share your complete journal (anonymize what you must) - without this it's not really possible to find the reason for the error