directReports is has systemFlags: FLAG_ATTR_NOT_REPLICATED in the schema definition. https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms- adls/f7cd6943-872d-423c-8009-bc8502485fab
hm, directReports is a linked reference to the value of the manager attribute and it should be maintained by the DC that was replicated to. But that seems to fail occasionally.