diff --git a/.changeset/hungry-islands-fly.md b/.changeset/hungry-islands-fly.md
new file mode 100644
index 000000000..000d4d49c
--- /dev/null
+++ b/.changeset/hungry-islands-fly.md
@@ -0,0 +1,5 @@
+---
+"inngest": patch
+---
+
+Do not swallow JSON parsing errors when syncing
diff --git a/packages/inngest/src/components/InngestCommHandler.ts b/packages/inngest/src/components/InngestCommHandler.ts
index d7acdb20e..8a83892f1 100644
--- a/packages/inngest/src/components/InngestCommHandler.ts
+++ b/packages/inngest/src/components/InngestCommHandler.ts
@@ -1141,6 +1141,7 @@ export class InngestCommHandler<
       data = await res.json();
     } catch (err) {
       this.log("warn", "Couldn't unpack register response:", err);
+      throw err;
     }
     const { status, error, skipped, modified } = registerResSchema.parse(data);
 
diff --git a/packages/inngest/src/test/helpers.ts b/packages/inngest/src/test/helpers.ts
index 687b86f7e..5a4116c8c 100644
--- a/packages/inngest/src/test/helpers.ts
+++ b/packages/inngest/src/test/helpers.ts
@@ -606,7 +606,7 @@ export const testFramework = (
 
       describe("env detection and headers", () => {
         test("uses env headers from client", async () => {
-          nock("https://api.inngest.com").post("/fn/register").reply(200);
+          nock("https://api.inngest.com").post("/fn/register").reply(200, {});
 
           const ret = await run(
             [