diff --git a/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts b/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts
index d845bfc54..6c69a80cb 100644
--- a/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts
+++ b/packages/compiler/src/frontend/lowering/class-dynamic-dispatch.ts
@@ -5246,9 +5246,12 @@ export class ClassDynamicDispatch {
       owner = methodInfo.declarer;
       params = methodInfo.sig.params;
       // An untyped async method's `dyn` result is its promise's payload; the
-      // call answers the promise.
+      // call answers the promise. An async generator method answers its
+      // generator object, which its signature already returns.
       result =
-        methodInfo.sig.async === true && methodInfo.sig.ret.kind !== "promise"
+        methodInfo.sig.async === true &&
+        !methodInfo.sig.gen &&
+        methodInfo.sig.ret.kind !== "promise"
           ? { kind: "promise", inner: methodInfo.sig.ret }
           : methodInfo.sig.ret;
       callee = `%${owner.def.name}.${method}`;
diff --git a/packages/compiler/src/frontend/lowering/lower-classes.ts b/packages/compiler/src/frontend/lowering/lower-classes.ts
index a6dd6e3dd..10927e49b 100644
--- a/packages/compiler/src/frontend/lowering/lower-classes.ts
+++ b/packages/compiler/src/frontend/lowering/lower-classes.ts
@@ -6724,9 +6724,10 @@ function thunkAsyncSlot(
   if (overridden.sig.async !== true) return;
   const declarer = overridden.declarer;
   // The slot answers the body's promise: an untyped async method's `dyn`
-  // result is the promise's payload, so the slot's ABI is that promise.
+  // result is the promise's payload, so the slot's ABI is that promise. An
+  // async generator method's slot keeps its generator object.
   const ret: IrType =
-    overridden.sig.ret.kind === "promise"
+    overridden.sig.gen || overridden.sig.ret.kind === "promise"
       ? overridden.sig.ret
       : { kind: "promise", inner: overridden.sig.ret };
   declarer.returnAdapters ??= new Map();
diff --git a/tests/corpus/6419-untyped-async-package/main.ts b/tests/corpus/6419-untyped-async-package/main.ts
index e118adba4..9ec10f7c5 100644
--- a/tests/corpus/6419-untyped-async-package/main.ts
+++ b/tests/corpus/6419-untyped-async-package/main.ts
@@ -1,7 +1,8 @@
 // Untyped async methods of a package, reached through the package's own
 // untyped callers and prototype reflection, and overridden by a typed
-// subclass.
-import { Pool, Schema, limiter, prototypeNames, validateAll } from "token-pool";
+// subclass. An async generator method called from the package answers its
+// generator object.
+import { Pool, Schema, limiter, listIssues, prototypeNames, validateAll } from "token-pool";
 
 class CountingPool extends Pool {
   acquired = 0;
@@ -25,6 +26,7 @@ async function main(): Promise<void> {
   console.log(await Promise.all([run(async () => 1), run(async () => 2)]));
   const schema = new Schema((value) => typeof value === "number");
   console.log(await validateAll(schema, [1, "x", 3]));
+  console.log(await listIssues(schema, ["p", 5, "q"]));
   console.log(await schema.parseAsync(4));
   try {
     await schema.parseAsync("y");
diff --git a/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.d.ts b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.d.ts
index a7a8459ac..ed0c82579 100644
--- a/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.d.ts
+++ b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.d.ts
@@ -10,6 +10,8 @@ export declare class Schema {
     constructor(check: (value: unknown) => boolean);
     safeParseAsync(data: unknown): Promise<any>;
     parseAsync(data: unknown): Promise<any>;
+    issues(values: unknown[]): AsyncGenerator<any>;
 }
 export declare function validateAll(schema: Schema, values: unknown[]): Promise<string>;
+export declare function listIssues(schema: Schema, values: unknown[]): Promise<string>;
 export declare function prototypeNames(): string;
diff --git a/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.js b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.js
index 9140e50af..04935ff29 100644
--- a/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.js
+++ b/tests/corpus/6419-untyped-async-package/node_modules/token-pool/index.js
@@ -88,6 +88,12 @@ class Schema {
         this.results.push(this.check(data) ? { success: true, data } : { success: false, issue: "invalid " + data });
         return this.results.pop();
     }
+    async *issues(values) {
+        for (const value of values) {
+            const result = await this.safeParseAsync(value);
+            if (!result.success) yield result.issue;
+        }
+    }
     async parseAsync(data) {
         const result = await this.safeParseAsync(data);
         if (result.success) return result.data;
@@ -104,6 +110,13 @@ async function validateAll(schema, values) {
     return out.join(", ");
 }
 exports.validateAll = validateAll;
+async function listIssues(schema, values) {
+    const out = [];
+    const it = schema.issues(values);
+    for (let step = await it.next(); !step.done; step = await it.next()) out.push(step.value);
+    return out.join(", ");
+}
+exports.listIssues = listIssues;
 function prototypeNames() {
     return typeof Schema.prototype.parseAsync + " " + typeof Schema.prototype.safeParseAsync;
 }