Did you also check VLAN enable on the top of the vlan member page? How are you connecting clients to the various vlans, are you just using the four ports, four clients, a multi-vlan ap or a managed vlan capble switch? Why isn't vlan 1 inter-vlan enabled? When pinging from diagnotic utility your using vlan 1 and if it's set to inter-vlan the router won't route to the other vlans from it.
I assume your managed switch is acting as the DHCP server then. You could make the RV the dhcp server and eliminate the servers on the switch or you might try changing the default router setting in each vlan dhcp pool on the switch to the ip of the vlan interface of on the RV since that's what you want to do your routing. I'm not sure if that will screw up you dhcp server Pol though which is why it might be easiest just to let the RV handle that too.
I had a simiar but opposite issue a couple of weeks ago where I wanted my L3 switch to handle interv-vlan routing but wanted the vlan 1 dhcp server on the RV320 and the fix recommended was to move the dhcp server to the switch so the default router for that vlan was the ip of the switch vlan interface, SVI. Your SVI is on the RV but in the switch you're provably telling to use the ip of your dhcp server.
Disclaimer: I could be completely wrong but based on my limited knowledge I think that's the root of your issue.
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