I think i see the problem.
, [snmp:snmp], [snmp_ds:no-snmp], [tcp:tcp]
SNMP host should look like this for example
, [snmp:snmp], [snmp_ds:snmp-v2]
agent host has this tags
, [snmp_ds:no-snmp], [tcp:tcp]
In your case the extra [snmp:snmp] leads to the SNMP calls.
Now the why. I think that in your 1.6 installation the host tag “agent” was modified.
If this tag was modified manually before the upgrade to 2.0 then it is a little bit broken after the upgrade.
This can only be fixed manually on the command line. Attention backup the host tag file before modifying.