ldapsearch gives partial results

Hello

I have a problem with ldapsearch sometimes returning partial results. The result code is still 0 (success), but the list of object is limited to 63 or 127 (it seems there is a 2^n-1 pattern) items instead of expected 136. It will happen after 10 to 15 requests that return the complete result.

The filter is below. It can happen even if only DN are requested (no attributes): (&(|(ou=example1)(ou=example2))(objectClass=netExamplePerson) (!(netExampleHidden=TRUE))(netExempleActive=TRUE))

This is OpenLDAP 2.4.40, BDB 4.8.30. All attributes in the filter are indexed, and it happens after the openldap-data directory has been cleared and everything has been reconstructed from scratch.