Comment 22 for bug 1767105

To follow up with results of testing non-file locking: yep, the end user we were working with initially had this in their config, as Rafael said:

Mutex file:${APACHE_LOCK_DIR} default

and we asked them to update it to not use file for ldap, by changing to:

Mutex file:${APACHE_LOCK_DIR} default
Mutex sem ldap-cache

After that change (done about 1 month ago) they restarted and have not seen the problem happen again. I don't have any answer to why exactly they set the default to file locking.