diff --git a/packages/app-elements/src/ui/forms/InputCheckboxGroup/HookedInputCheckboxGroup.test.tsx b/packages/app-elements/src/ui/forms/InputCheckboxGroup/HookedInputCheckboxGroup.test.tsx
new file mode 100644
index 000000000..d7689b4e4
--- /dev/null
+++ b/packages/app-elements/src/ui/forms/InputCheckboxGroup/HookedInputCheckboxGroup.test.tsx
@@ -0,0 +1,108 @@
+import { fireEvent, render } from "@testing-library/react"
+import { FormProvider, useForm, useFormContext } from "react-hook-form"
+import { Text } from "#ui/atoms/Text"
+import { HookedInputCheckboxGroup } from "./HookedInputCheckboxGroup"
+
+interface FormValues {
+  items: Array<{
+    value: string
+    quantity?: number
+    reason?: string
+  }>
+}
+
+const options = [
+  {
+    value: "BABYBIBXA19D9D000000XXXX",
+    content: (
+      <Text size="small" tag="div" weight="bold">
+        Gray Baby Bib with Black Logo
+      </Text>
+    ),
+    quantity: {
+      min: 1,
+      max: 5,
+    },
+  },
+  {
+    value: "BASEBHAT000000FFFFFFXXXX",
+    content: (
+      <Text size="small" tag="div" weight="bold">
+        Black Baseball Hat with White Logo
+      </Text>
+    ),
+    quantity: {
+      min: 1,
+      max: 7,
+    },
+  },
+]
+
+function SetReasonButton(): React.JSX.Element {
+  const { setValue } = useFormContext<FormValues>()
+
+  return (
+    <button
+      type="button"
+      onClick={() => {
+        setValue("items.0.reason", "Damaged")
+      }}
+    >
+      Set reason
+    </button>
+  )
+}
+
+function ValuesPreview(): React.JSX.Element {
+  const { watch } = useFormContext<FormValues>()
+
+  return <pre data-testid="values">{JSON.stringify(watch("items"))}</pre>
+}
+
+function TestComponent(): React.JSX.Element {
+  const methods = useForm<FormValues>({
+    defaultValues: {
+      items: [
+        {
+          value: "BABYBIBXA19D9D000000XXXX",
+          quantity: 2,
+        },
+        {
+          value: "BASEBHAT000000FFFFFFXXXX",
+          quantity: 3,
+        },
+      ],
+    },
+  })
+
+  return (
+    <FormProvider {...methods}>
+      <SetReasonButton />
+      <ValuesPreview />
+      <HookedInputCheckboxGroup name="items" title="Items" options={options} />
+    </FormProvider>
+  )
+}
+
+describe("HookedInputCheckboxGroup", () => {
+  test("preserves extra item fields after nested setValue and toggle", () => {
+    const { getAllByTestId, getByRole, getByTestId } = render(<TestComponent />)
+
+    fireEvent.click(getByRole("button", { name: "Set reason" }))
+    expect(getByTestId("values").textContent).toContain('"reason":"Damaged"')
+
+    const [, secondItem] = getAllByTestId("InputCheckboxGroupItem")
+    assertToBeDefined(secondItem)
+
+    fireEvent.click(secondItem)
+
+    const values = JSON.parse(getByTestId("values").textContent ?? "null")
+    expect(values).toEqual([
+      {
+        value: "BABYBIBXA19D9D000000XXXX",
+        quantity: 2,
+        reason: "Damaged",
+      },
+    ])
+  })
+})
diff --git a/packages/app-elements/src/ui/forms/InputCheckboxGroup/HookedInputCheckboxGroup.tsx b/packages/app-elements/src/ui/forms/InputCheckboxGroup/HookedInputCheckboxGroup.tsx
index dd148db8b..bc71affa2 100644
--- a/packages/app-elements/src/ui/forms/InputCheckboxGroup/HookedInputCheckboxGroup.tsx
+++ b/packages/app-elements/src/ui/forms/InputCheckboxGroup/HookedInputCheckboxGroup.tsx
@@ -20,7 +20,7 @@ export interface HookedInputCheckboxGroupProps
 export const HookedInputCheckboxGroup: React.FC<
   HookedInputCheckboxGroupProps
 > = ({ name, ...props }) => {
-  const { control } = useFormContext()
+  const { control, getValues } = useFormContext()
   const feedback = useValidationFeedback(name)
 
   return (
@@ -31,9 +31,29 @@ export const HookedInputCheckboxGroup: React.FC<
         <InputCheckboxGroup
           {...props}
           feedback={feedback}
-          defaultValues={field.value ?? []}
+          defaultValues={Array.isArray(field.value) ? field.value : []}
           onChange={(values) => {
-            field.onChange(values)
+            // Preserve any extra fields (e.g. `reason`) that the consumer
+            // stored on existing items via setValue. We need the latest form
+            // snapshot here because field.value can lag behind nested updates.
+            const currentValue = getValues(name)
+            const current: Array<{ value: string }> = Array.isArray(
+              currentValue,
+            )
+              ? currentValue.filter(
+                  (v): v is { value: string } =>
+                    typeof v === "object" &&
+                    v !== null &&
+                    "value" in v &&
+                    typeof (v as { value: unknown }).value === "string",
+                )
+              : []
+            field.onChange(
+              values.map((item) => {
+                const existing = current.find((v) => v.value === item.value)
+                return existing != null ? { ...existing, ...item } : item
+              }),
+            )
           }}
         />
       )}