diff --git a/.changeset/moody-clocks-repeat.md b/.changeset/moody-clocks-repeat.md
new file mode 100644
index 00000000000..cbda9da8db4
--- /dev/null
+++ b/.changeset/moody-clocks-repeat.md
@@ -0,0 +1,8 @@
+---
+"@clerk/clerk-js": patch
+"@clerk/backend": patch
+"@clerk/clerk-react": patch
+"@clerk/types": patch
+---
+
+Update type of `__experimental_factorVerificationAge` to be `[number, number] | null`.
diff --git a/packages/backend/src/tokens/authObjects.ts b/packages/backend/src/tokens/authObjects.ts
index e64abce784c..84e00271c41 100644
--- a/packages/backend/src/tokens/authObjects.ts
+++ b/packages/backend/src/tokens/authObjects.ts
@@ -40,7 +40,7 @@ export type SignedInAuthObject = {
    * [fistFactorAge, secondFactorAge]
    * @experimental This API is experimental and may change at any moment.
    */
-  __experimental_factorVerificationAge: [number | null, number | null];
+  __experimental_factorVerificationAge: [number, number] | null;
   getToken: ServerGetToken;
   has: CheckAuthorizationWithCustomPermissions;
   debug: AuthObjectDebug;
@@ -64,7 +64,7 @@ export type SignedOutAuthObject = {
    * [fistFactorAge, secondFactorAge]
    * @experimental This API is experimental and may change at any moment.
    */
-  __experimental_factorVerificationAge: [null, null];
+  __experimental_factorVerificationAge: null;
   getToken: ServerGetToken;
   has: CheckAuthorizationWithCustomPermissions;
   debug: AuthObjectDebug;
@@ -100,7 +100,7 @@ export function signedInAuthObject(
     org_slug: orgSlug,
     org_permissions: orgPermissions,
     sub: userId,
-    fva: __experimental_factorVerificationAge,
+    fva,
   } = sessionClaims;
   const apiClient = createBackendApiClient(authenticateContext);
   const getToken = createGetToken({
@@ -109,6 +109,9 @@ export function signedInAuthObject(
     fetcher: async (...args) => (await apiClient.sessions.getToken(...args)).jwt,
   });
 
+  // fva can be undefined for instances that have not opt-in
+  const __experimental_factorVerificationAge = fva ?? null;
+
   return {
     actor,
     sessionClaims,
@@ -138,7 +141,7 @@ export function signedOutAuthObject(debugData?: AuthObjectDebugData): SignedOutA
     orgRole: null,
     orgSlug: null,
     orgPermissions: null,
-    __experimental_factorVerificationAge: [null, null],
+    __experimental_factorVerificationAge: null,
     getToken: () => Promise.resolve(null),
     has: () => false,
     debug: createDebug(debugData),
diff --git a/packages/clerk-js/src/core/resources/Session.ts b/packages/clerk-js/src/core/resources/Session.ts
index 7a32e025a5e..3307d7bd981 100644
--- a/packages/clerk-js/src/core/resources/Session.ts
+++ b/packages/clerk-js/src/core/resources/Session.ts
@@ -39,7 +39,7 @@ export class Session extends BaseResource implements SessionResource {
   actor!: ActJWTClaim | null;
   user!: UserResource | null;
   publicUserData!: PublicUserData;
-  __experimental_factorVerificationAge: [number | null, number | null] = [null, null];
+  __experimental_factorVerificationAge: [number, number] | null = null;
   expireAt!: Date;
   abandonAt!: Date;
   createdAt!: Date;
diff --git a/packages/clerk-js/src/utils/memoizeStateListenerCallback.ts b/packages/clerk-js/src/utils/memoizeStateListenerCallback.ts
index cfcac5aa57e..a48efc48397 100644
--- a/packages/clerk-js/src/utils/memoizeStateListenerCallback.ts
+++ b/packages/clerk-js/src/utils/memoizeStateListenerCallback.ts
@@ -51,10 +51,12 @@ function userMembershipsChanged(prev: UserResource, next: UserResource): boolean
 }
 
 function sessionFVAChanged(prev: SessionResource, next: SessionResource): boolean {
-  return (
-    prev.__experimental_factorVerificationAge[0] !== next.__experimental_factorVerificationAge[0] ||
-    prev.__experimental_factorVerificationAge[1] !== next.__experimental_factorVerificationAge[1]
-  );
+  const prevFVA = prev.__experimental_factorVerificationAge;
+  const nextFVA = next.__experimental_factorVerificationAge;
+  if (prevFVA !== null && nextFVA !== null) {
+    return prevFVA[0] !== nextFVA[0] || prevFVA[1] !== nextFVA[1];
+  }
+  return prevFVA !== nextFVA;
 }
 
 function sessionUserMembershipPermissionsChanged(prev: SessionResource, next: SessionResource): boolean {
diff --git a/packages/react/src/contexts/AuthContext.ts b/packages/react/src/contexts/AuthContext.ts
index 614afb57f15..a17cfb43dfb 100644
--- a/packages/react/src/contexts/AuthContext.ts
+++ b/packages/react/src/contexts/AuthContext.ts
@@ -9,5 +9,5 @@ export const [AuthContext, useAuthContext] = createContextAndHook<{
   orgRole: OrganizationCustomRoleKey | null | undefined;
   orgSlug: string | null | undefined;
   orgPermissions: OrganizationCustomPermissionKey[] | null | undefined;
-  __experimental_factorVerificationAge: [number | null, number | null];
+  __experimental_factorVerificationAge: [number, number] | null;
 }>('AuthContext');
diff --git a/packages/react/src/utils/deriveState.ts b/packages/react/src/utils/deriveState.ts
index 86885405616..c301d471238 100644
--- a/packages/react/src/utils/deriveState.ts
+++ b/packages/react/src/utils/deriveState.ts
@@ -48,9 +48,9 @@ const deriveFromClientSideState = (state: Resources) => {
   const user = state.user;
   const sessionId: string | null | undefined = state.session ? state.session.id : state.session;
   const session = state.session;
-  const __experimental_factorVerificationAge: [number | null, number | null] = state.session
+  const __experimental_factorVerificationAge: [number, number] | null = state.session
     ? state.session.__experimental_factorVerificationAge
-    : [null, null];
+    : null;
   const actor = session?.actor;
   const organization = state.organization;
   const orgId: string | null | undefined = state.organization ? state.organization.id : state.organization;
diff --git a/packages/types/src/json.ts b/packages/types/src/json.ts
index ab674ba6ea9..f01d00870df 100644
--- a/packages/types/src/json.ts
+++ b/packages/types/src/json.ts
@@ -110,7 +110,7 @@ export interface SessionJSON extends ClerkResourceJSON {
    * [fistFactorAge, secondFactorAge]
    * @experimental This API is experimental and may change at any moment.
    */
-  factor_verification_age: [number | null, number | null];
+  factor_verification_age: [number, number] | null;
   expire_at: number;
   abandon_at: number;
   last_active_at: number;
diff --git a/packages/types/src/jwtv2.ts b/packages/types/src/jwtv2.ts
index c76f25057a5..73ef4232f4d 100644
--- a/packages/types/src/jwtv2.ts
+++ b/packages/types/src/jwtv2.ts
@@ -107,7 +107,7 @@ export interface JwtPayload extends CustomJwtSessionClaims {
    * [fistFactorAge, secondFactorAge]
    * @experimental This API is experimental and may change at any moment.
    */
-  fva: [number | null, number | null];
+  fva?: [number, number];
 
   /**
    * Any other JWT Claim Set member.
diff --git a/packages/types/src/session.ts b/packages/types/src/session.ts
index 43ed41bc88a..ab34ff39ccf 100644
--- a/packages/types/src/session.ts
+++ b/packages/types/src/session.ts
@@ -61,7 +61,7 @@ export interface SessionResource extends ClerkResource {
    * [fistFactorAge, secondFactorAge]
    * @experimental This API is experimental and may change at any moment.
    */
-  __experimental_factorVerificationAge: [number | null, number | null];
+  __experimental_factorVerificationAge: [number, number] | null;
   lastActiveToken: TokenResource | null;
   lastActiveOrganizationId: string | null;
   lastActiveAt: Date;
diff --git a/packages/types/src/ssr.ts b/packages/types/src/ssr.ts
index d215a283b9d..0f7773aa08b 100644
--- a/packages/types/src/ssr.ts
+++ b/packages/types/src/ssr.ts
@@ -20,5 +20,5 @@ export type InitialState = Serializable<{
   orgSlug: string | undefined;
   orgPermissions: OrganizationCustomPermissionKey[] | undefined;
   organization: OrganizationResource | undefined;
-  __experimental_factorVerificationAge: [number | null, number | null];
+  __experimental_factorVerificationAge: [number, number];
 }>;