diff --git a/server/src/internal/billing/v2/actions/attach/errors/handleStripeCheckoutErrors.ts b/server/src/internal/billing/v2/actions/attach/errors/handleStripeCheckoutErrors.ts
index a2157525d..28b47b6c8 100644
--- a/server/src/internal/billing/v2/actions/attach/errors/handleStripeCheckoutErrors.ts
+++ b/server/src/internal/billing/v2/actions/attach/errors/handleStripeCheckoutErrors.ts
@@ -53,6 +53,8 @@ export const handleStripeCheckoutErrors = ({
 		autumnBillingPlan,
 	});
 
+	console.log("recurringIntervals", recurringIntervals);
+
 	// If we have more than one unique recurring interval, throw an error
 	if (recurringIntervals.size > 1) {
 		throw new RecaseError({
diff --git a/server/tests/integration/billing/attach/checkout/stripe-checkout/stripe-checkout-multi-interval.test.ts b/server/tests/integration/billing/attach/checkout/stripe-checkout/stripe-checkout-multi-interval.test.ts
index 2aca0a77e..072812d22 100644
--- a/server/tests/integration/billing/attach/checkout/stripe-checkout/stripe-checkout-multi-interval.test.ts
+++ b/server/tests/integration/billing/attach/checkout/stripe-checkout/stripe-checkout-multi-interval.test.ts
@@ -336,3 +336,48 @@ test.concurrent(`${chalk.yellowBright("stripe-checkout: annual with allocated us
 		latestInvoiceProductId: proAnnual.id,
 	});
 });
+
+test.concurrent(`${chalk.yellowBright("setup-payment: monthly plan + one-time payment - invoices paid after trial")}`, async () => {
+	const premium = products.base({
+		id: "premium",
+		items: [
+			items.annualPrice({ price: 50 }),
+			items.oneOffMessages({ price: 100, billingUnits: 100, includedUsage: 0 }),
+		],
+	});
+
+	const { customerId, autumnV1 } = await initScenario({
+		customerId: "setup-payment-monthly-oneoff",
+		setup: [s.customer({}), s.products({ list: [premium] })],
+		actions: [],
+	});
+
+	// Attach product with quantity option for the one-off prepaid feature
+	const res = await autumnV1.billing.attach({
+		customer_id: customerId,
+		product_id: premium.id,
+		redirect_mode: "if_required",
+		options: [
+			{
+				feature_id: TestFeature.Messages,
+				quantity: 100,
+			},
+		],
+	});
+
+	await completeStripeCheckoutForm({ url: res.payment_url! });
+
+	const customer = await autumnV1.customers.get(customerId);
+
+	await expectProductActive({
+		customer,
+		productId: premium.id,
+	});
+
+	await expectCustomerFeatureCorrect({
+		customer,
+		featureId: TestFeature.Messages,
+		balance: 100,
+		usage: 0,
+	});
+});
diff --git a/server/tests/integration/billing/stripe-webhooks/checkout-session-completed/setup-payment-after-trial.test.ts b/server/tests/integration/billing/stripe-webhooks/checkout-session-completed/setup-payment-after-trial.test.ts
index cd1d28b99..f140095fa 100644
--- a/server/tests/integration/billing/stripe-webhooks/checkout-session-completed/setup-payment-after-trial.test.ts
+++ b/server/tests/integration/billing/stripe-webhooks/checkout-session-completed/setup-payment-after-trial.test.ts
@@ -1,10 +1,10 @@
 import { expect, test } from "bun:test";
+import { FreeTrialDuration } from "@autumn/shared";
 import { completeSetupPaymentForm } from "@tests/utils/browserPool";
 import { items } from "@tests/utils/fixtures/items.js";
 import { products } from "@tests/utils/fixtures/products.js";
 import { advanceTestClock } from "@tests/utils/stripeUtils.js";
 import { initScenario, s } from "@tests/utils/testInitUtils/initScenario.js";
-import { FreeTrialDuration } from "@autumn/shared";
 import chalk from "chalk";
 
 /**
diff --git a/vite/src/components/forms/attach-v2/hooks/useAttachRequestBody.ts b/vite/src/components/forms/attach-v2/hooks/useAttachRequestBody.ts
index 541940a29..f4215abbc 100644
--- a/vite/src/components/forms/attach-v2/hooks/useAttachRequestBody.ts
+++ b/vite/src/components/forms/attach-v2/hooks/useAttachRequestBody.ts
@@ -6,7 +6,7 @@ import {
 	type FreeTrialDuration,
 	type PlanTiming,
 	type ProductItem,
-	ProductItemInterval,
+	type ProductItemInterval,
 	type ProductV2,
 	UsageModel,
 } from "@autumn/shared";
@@ -117,8 +117,7 @@ export function buildAttachRequestBody({
 	if (items !== null) {
 		body.items = items.map((item) => ({
 			...item,
-			interval: (item.interval ||
-				ProductItemInterval.Month) as ProductItemInterval,
+			interval: (item.interval ?? null) as ProductItemInterval | null,
 		}));
 	}