houdini: Getting "Cannot convert undefined or null" errors on queries after upgrading to latest release

I was on the 0.5.1-kit.5 release previously and my primary queries were working (though I was still struggling with subscriptions). I upgraded to latest, regenerated the schema, and now I am getting the following error, even after simplifying my schema to a single test query.

Cannot convert undefined or null to object
TypeError: Cannot convert undefined or null to object
    at Function.entries (<anonymous>)
    at Cache._write (/$houdini/runtime/cache/cache.js:232:45)
    at Cache.write (/$houdini/runtime/cache/cache.js:19:14)
    at Object.writeData (/$houdini/runtime/query.js:58:19)
    at index.svelte:60:35
    at Object.$$render (<PATH>/node_modules/svelte/internal/index.js:1380:22)
    at Object.default (root.svelte:33:46)
    at eval (<PATH>src/routes/__layout.svelte:44:36)
    at Object.$$render (<PATH>/node_modules/svelte/internal/index.js:1380:22)
    at root.svelte:31:44