dummyButtondummyButtonThe issue was due to specific case when parent item for item in itembox result was resided in inactive list and item permissions were identified by assigned usergroups custom field and listownerprivs Read access were set for the parent and child lists for the user's usergroups.
In that case query that generated by GeneratePrivCheckForItemsRetrieval method checked only listownerprivs but didn't check if the list is active or not.