Excessive snmp requests with a community string I am not using

Check if you have the snmp.community property set anywhere including at the root group level. Properties get inherited so it can be easy for some properties (especially when using the Wizard) to get set at a higher level and flow down. It's also possible that ProperySources might do a snmp check but it wouldn't be nearly that frequently.

Also if you were doing v3 previously, verify that is still working. If v3 stops working LM might attempt to downgrade to v2 and perhaps use a "public" default value.