SNMP doesn’t work on HP procurve switch with a ip route 0.0.0.0 0.0.0.0 INSERTROUTINGVLAN, but does work with a ip default-gateway INSERTSWITCHMANAGEMENTIP. So the switch has to have a default gateway to work.
To fix this issue and keep an ip route 0.0.0.0 0.0.0.0 ROUTINGVLANIP then run the following command
snmp-server response-source INSERTSWITCHMANAGEMENTIP