When I upgraded from 2.2.2 to 2.2.3 I receive a lot of erros like:
3656:20140509:001126.314 temporarily disabling SNMP agent checks on host "PPPoE Krasow - Area9": host unavailable

3656:20140509:001126.314 temporarily disabling SNMP agent checks on host "PPPoE Krasow - Area9": host unavailable

3659:20140509:001054.749 SNMP agent item "nstremeDual" on host "PPPoE Krasow - Area9" failed: another network error, wait for 15 seconds

3666:20140509:002416.057 cannot send list of active checks to [127.0.0.1]: host [pies] not found

but also :

3660:20140509:001121.957 enabling SNMP agent checks on host "PPPoE Dziezgow - Area10": host became available

As result all SNMP hosts are being disabled, but from time to time become also enabled (flapping). Anyway graphs for related SNMP items contain holes or nothing is drawn.

Issue is related with SNMP checks only, all items for zabbix agent based items are graphed properly.

The configuration of zabbix server is identical, as in case of 2.2.2 (which is working fine). As a trial I changed binaries only to 2.2.2 version and there is no issue.

For sure this is not an issue with SNMP connectivity ( I checked it on linux console with snmpwalk and snmpget)
I look also at number of pollers and it does not look as an issue.