jeffg: diq, i took a peek at that capture you sent. looks as if your A10 device's agent gets sad when we send a get-bulk that includes a bunch of objects within the A10 private-enterprise MIB – responds with a generic-error, which means "wtf" in snmp.

A10's enterprise is 22610.

Workaround is to set max-vars-per-pdu to 1.

I've notified A10 of the issue.