BadStatusLine exception from zapi.item.get (ZabbixAPI/pyzabbix) when multithreading

[MadCowMoo]

I am running a multithreaded process against the ZabbixAPI (pyzabbix) in Python:
pool.apply_async(getLatestData, args = (item, ), callback = outputSenderLine)
Where "item" is set by a for-loop to either 'CPU Utilization Percent' or 'Memory Percentage Used'

In "getLatestData,"...

[Zablux01]

Hello

Do you understand this ?

#!/usr/bin/env python
import json
from pyzabbix import ZabbixAPI, ZabbixAPIException
…
zapi.login(user = myusr,password = mypwd)
…
t = zapi.do_request('template.get', {"output": "templateid",...