If one of queries are failed while configuration update process, Zabbix server/proxy lost that type of configuration cache. For example, items configuration lost if the query failed:
select i.itemid,i.hostid,h.proxy_hostid,i.type,i.data_type,i.value_type,i.key_,i.snmp_community,i.snmp_oid,i.port,i.snmpv3_securityname,i.snmpv3_securitylevel,i.snmpv3_authpassphrase,i.snmpv3_privpassphrase,i.ipmi_sensor,i.delay,i.delay_flex,i.trapper_hosts,i.logtimefmt,i.params,i.state,i.authtype,i.username,i.password,i.publickey,i.privatekey,i.flags,i.interfaceid,i.snmpv3_authprotocol,i.snmpv3_privprotocol,i.snmpv3_contextname,i.lastlogsize,i.mtime from items i,hosts h where i.hostid=h.hostid and h.status=0 and i.status=0