I have template, which uses scripts from https://github.com/jjmartres/Zabbix

After upgrade to 3.4 i see many errors in log like this:

22715:20170827:034203.325 /usr/local/share/gems/gems/snmp-1.2.0/lib/snmp/manager.rb:245:in `get': host Fortigate 1000C Abovyan not responding (SNMP::RequestTimeout)
from /usr/lib/zabbix/externalscripts/if.vdom:70:in `block in <main>'
from /usr/local/share/gems/gems/snmp-1.2.0/lib/snmp/manager.rb:218:in `open'
from /usr/lib/zabbix/externalscripts/if.vdom:69:in `<main>'

Short time after start i see same symptoms as in ZBX-12549 - server stops collecting data and agents become unreachable.