Well, it turned out the DHCP service didn't get restarted, but I also didn't have the popup asking me about a restart of services, so I had no idea it was needed. Is there any way to get the services to auto-restart periodically if needed?
Nevermind, found my issue. I was passing the data with "data=data" instead of "json=data". When I fix that (and and a "View" field), it works. Would've been nice to get a more useful error message, though.