diff --git a/src/bounties/ingest.ts b/src/bounties/ingest.ts
index 46e34b5a04..fa582dd348 100644
--- a/src/bounties/ingest.ts
+++ b/src/bounties/ingest.ts
@@ -21,8 +21,27 @@ export function normalizeGittBountySnapshot(payload: unknown): BountyRecord[] {
   // empty list — matching how every other non-object value already yields `[]` — instead of throwing.
   const data = payload as GittIssueListPayload | null | undefined;
   return (data?.issues ?? []).flatMap((issue) => {
-    if (issue.id === undefined || !issue.repository_full_name || !issue.issue_number || !issue.status) return [];
-    const amountText = issue.bounty_alpha ?? (issue.bounty_amount === undefined ? undefined : String(issue.bounty_amount));
+    // #9313: `issue` is cast from an UNTRUSTED Gitt payload, so its declared field types are not guaranteed at
+    // runtime. Type-guard every field the BountyRecord contract requires (id: string|number, repoFullName:
+    // string, issueNumber: number, status: string) -- mirroring registry/normalize.ts's typed value guards --
+    // so a wrong-typed field drops the whole record instead of being trusted into a mistyped BountyRecord.
+    if (
+      (typeof issue.id !== "string" && typeof issue.id !== "number") ||
+      typeof issue.repository_full_name !== "string" ||
+      !issue.repository_full_name ||
+      typeof issue.issue_number !== "number" ||
+      !Number.isFinite(issue.issue_number) ||
+      typeof issue.status !== "string" ||
+      !issue.status
+    ) {
+      return [];
+    }
+    const amountText =
+      typeof issue.bounty_alpha === "string"
+        ? issue.bounty_alpha
+        : typeof issue.bounty_amount === "number" && Number.isFinite(issue.bounty_amount)
+          ? String(issue.bounty_amount)
+          : undefined;
     return [
       {
         id: String(issue.id),
diff --git a/test/unit/bounties-ingest.test.ts b/test/unit/bounties-ingest.test.ts
new file mode 100644
index 0000000000..3401639b01
--- /dev/null
+++ b/test/unit/bounties-ingest.test.ts
@@ -0,0 +1,60 @@
+import { describe, expect, it } from "vitest";
+
+import { normalizeGittBountySnapshot } from "../../src/bounties/ingest";
+
+// #9313: normalizeGittBountySnapshot parses an UNTRUSTED Gitt payload (`unknown`), so its declared field types
+// don't hold at runtime. These pin the typed value guards: a wrong-typed required field drops the whole record
+// rather than being trusted into a mistyped BountyRecord, and a wrong-typed/non-finite amount degrades to
+// undefined without dropping the record.
+const validIssue: Record<string, unknown> = {
+  id: 42,
+  repository_full_name: "owner/repo",
+  issue_number: 7,
+  status: "open",
+  bounty_amount: 5,
+};
+const snap = (issue: Record<string, unknown>) => normalizeGittBountySnapshot({ issues: [issue] });
+
+describe("normalizeGittBountySnapshot type guards (#9313)", () => {
+  it.each([
+    ["id neither string nor number", { id: {} }],
+    ["repoFullName not a string", { repository_full_name: 5 }],
+    ["repoFullName empty", { repository_full_name: "" }],
+    ["issueNumber not a number", { issue_number: "7" }],
+    ["issueNumber non-finite (NaN)", { issue_number: Number.NaN }],
+    ["status not a string", { status: 5 }],
+    ["status empty", { status: "" }],
+  ])("drops a record whose required field is wrong-typed: %s", (_label, override) => {
+    expect(snap({ ...validIssue, ...override })).toEqual([]);
+  });
+
+  it("keeps a well-typed record (string id) and takes amountText from bounty_alpha", () => {
+    const [record] = snap({ ...validIssue, id: "abc-1", bounty_alpha: "1 alpha", bounty_amount: undefined });
+    expect(record).toMatchObject({
+      id: "abc-1",
+      repoFullName: "owner/repo",
+      issueNumber: 7,
+      status: "open",
+      amountText: "1 alpha",
+    });
+  });
+
+  it("keeps a well-typed record (numeric id) and stringifies a finite bounty_amount when no bounty_alpha", () => {
+    const [record] = snap({ ...validIssue, id: 42, bounty_alpha: undefined, bounty_amount: 5 });
+    expect(record).toMatchObject({ id: "42", issueNumber: 7, amountText: "5" });
+  });
+
+  it("degrades a non-finite or absent amount to undefined without dropping the record", () => {
+    const infinite = snap({ ...validIssue, bounty_alpha: undefined, bounty_amount: Number.POSITIVE_INFINITY });
+    expect(infinite).toHaveLength(1);
+    expect(infinite[0]?.amountText).toBeUndefined();
+    const absent = snap({ ...validIssue, bounty_alpha: undefined, bounty_amount: undefined });
+    expect(absent).toHaveLength(1);
+    expect(absent[0]?.amountText).toBeUndefined();
+  });
+
+  it("returns [] for a null/malformed payload (unchanged fail-safe)", () => {
+    expect(normalizeGittBountySnapshot(null)).toEqual([]);
+    expect(normalizeGittBountySnapshot({})).toEqual([]);
+  });
+});