diff --git a/apps/admin-ui/src/components/ProductForm.tsx b/apps/admin-ui/src/components/ProductForm.tsx
index 091b84d..7d78f0d 100644
--- a/apps/admin-ui/src/components/ProductForm.tsx
+++ b/apps/admin-ui/src/components/ProductForm.tsx
@@ -123,21 +123,37 @@ const productValidationSchema = Yup.object().shape({
       }
       return true
     })
-    .test('quantity-feature', 'Every SKU must have a quantity feature', function (variants) {
+    .test('quantity-feature', 'Each SKU must have exactly one quantity feature', function (variants) {
       if (!Array.isArray(variants)) return true
       for (const variant of variants) {
         const attrs = variant?.attributes || []
-        const hasQuantity = attrs.some(
+        const quantityCount = attrs.filter(
           (a) => ((a as Attribute)?.featureName ?? '').trim().toLowerCase() === 'quantity'
-        )
-        if (!hasQuantity) {
+        ).length
+        if (quantityCount === 0) {
           return this.createError({ message: 'Every SKU must have a quantity feature' })
         }
+        if (quantityCount > 1) {
+          return this.createError({ message: 'Each SKU can have only one quantity feature' })
+        }
       }
       return true
     }),
 })
 
+// Collect every string message from a Formik errors tree (objects, arrays, strings).
+// Variant-level errors (e.g. 'Each SKU can have only one quantity feature') can get
+// hidden by Formik when index-level errors are also present, so we walk everything.
+const collectErrorMessages = (errors: unknown, depth = 0): string[] => {
+  if (depth > 6) return []
+  if (typeof errors === 'string') return [errors]
+  if (Array.isArray(errors)) return errors.flatMap((e) => collectErrorMessages(e, depth + 1))
+  if (errors && typeof errors === 'object') {
+    return Object.values(errors).flatMap((e) => collectErrorMessages(e, depth + 1))
+  }
+  return []
+}
+
 const ProductForm = forwardRef<ProductFormRef, ProductFormProps>(({
   mode,
   initialValues,
@@ -188,6 +204,20 @@ const ProductForm = forwardRef<ProductFormRef, ProductFormProps>(({
       initialValues={formInitialValues}
       validationSchema={productValidationSchema}
       onSubmit={(values) => {
+        // Normalize feature names before sending to backend: the mandatory
+        // 'quantity' feature must always go out lowercase (case-insensitive
+        // matching means 'Quantity'/'QUANTITY' are treated the same), and
+        // names are trimmed like the backend does.
+        const normalizedValues: ProductFormData = {
+          ...values,
+          variants: values.variants.map((v) => ({
+            ...v,
+            attributes: v.attributes.map((a) => ({
+              ...a,
+              featureName: isQuantityFeature(a) ? 'quantity' : (a.featureName ?? '').trim() || null,
+            })),
+          })),
+        }
         const images = variantImages.map((imgs) =>
           imgs.map((img) => ({ url: img.imgUrl, mimeType: img.mimeType }))
         )
@@ -203,7 +233,7 @@ const ProductForm = forwardRef<ProductFormRef, ProductFormProps>(({
             })
           })
         }
-        onSubmit(values, images, deletedKeys)
+        onSubmit(normalizedValues, images, deletedKeys)
       }}
       enableReinitialize
     >
@@ -323,13 +353,24 @@ const ProductForm = forwardRef<ProductFormRef, ProductFormProps>(({
                               <MyText style={tw`text-gray-600 text-xs ml-0.5`}>Add</MyText>
                             </TouchableOpacity>
                           </View>
-                          {variant.attributes.map((attr, aIndex) => (
+                          {variant.attributes.map((attr, aIndex) => {
+                            const quantityCount = variant.attributes.filter(isQuantityFeature).length
+                            // Quantity features are locked (non-editable), but if there
+                            // are duplicates (e.g. 'quantity' + 'Quantity') the user must
+                            // be able to delete the extras to fix the form.
+                            const canDelete = variant.attributes.length > 1 && (!isQuantityFeature(attr) || quantityCount > 1)
+                            return (
                             <View key={aIndex} style={tw`flex-row items-center mb-2 gap-2`}>
                               <View style={tw`flex-1`}>
                                 <MyTextInput
                                   placeholder="Name"
                                   value={attr.featureName ?? ''}
-                                  onChangeText={handleChange(`variants.${vIndex}.attributes.${aIndex}.featureName`)}
+                                  onChangeText={(text) =>
+                                    setFieldValue(
+                                      `variants.${vIndex}.attributes.${aIndex}.featureName`,
+                                      text.trim().toLowerCase() === 'quantity' ? 'quantity' : text
+                                    )
+                                  }
                                   editable={!isQuantityFeature(attr)}
                                   style={isQuantityFeature(attr) ? tw`text-gray-400` : undefined}
                                 />
@@ -341,13 +382,14 @@ const ProductForm = forwardRef<ProductFormRef, ProductFormProps>(({
                                   onChangeText={handleChange(`variants.${vIndex}.attributes.${aIndex}.featureValue`)}
                                 />
                               </View>
-                              {variant.attributes.length > 1 && !isQuantityFeature(attr) && (
+                              {canDelete && (
                                 <TouchableOpacity onPress={() => removeAttr(aIndex)}>
                                   <MaterialIcons name="close" size={18} color="#EF4444" />
                                 </TouchableOpacity>
                               )}
                             </View>
-                          ))}
+                            )
+                          })}
                           <View style={tw`flex-row items-center self-start`}>
                             <TouchableOpacity
                               onPress={() => pushAttr(defaultAttribute())}
@@ -534,18 +576,10 @@ const ProductForm = forwardRef<ProductFormRef, ProductFormProps>(({
             onPress={async () => {
               const validationErrors = await validateForm()
               if (Object.keys(validationErrors).length > 0) {
-                const variantsError = validationErrors.variants
-                const firstVariantErrors = Array.isArray(variantsError)
-                  ? (variantsError[0] as Record<string, unknown> | undefined) || {}
-                  : {}
-                const message = (firstVariantErrors.price as string | undefined)
-                  || (firstVariantErrors.marketPrice as string | undefined)
-                  || (firstVariantErrors.flashPrice as string | undefined)
-                  || (firstVariantErrors.attributes as string | undefined)
-                  || validationErrors.name
-                  || validationErrors.storeId
-                  || variantsError
-                Alert.alert('Check your form', String(message || 'Please fix the highlighted fields'))
+                const variantsMessages = collectErrorMessages(validationErrors.variants)
+                const allMessages = collectErrorMessages(validationErrors)
+                const message = variantsMessages[0] || allMessages[0] || 'Please fix the highlighted fields'
+                Alert.alert('Check your form', String(message))
                 return
               }
               handleSubmit()
@@ -554,7 +588,12 @@ const ProductForm = forwardRef<ProductFormRef, ProductFormProps>(({
             style={tw`px-4 py-3 rounded-lg shadow-lg items-center mt-4 ${isLoading ? 'bg-gray-400' : 'bg-blue-500'}`}
           >
             <MyText style={tw`text-white text-lg font-bold`}>
-              {isLoading ? 'Creating...' : 'Create Product'}
+              {(() => {
+                if (mode === 'edit') {
+                  return isLoading ? 'Saving...' : 'Save Changes'
+                }
+                return isLoading ? 'Creating...' : 'Create Product'
+              })()}
             </MyText>
           </TouchableOpacity>
         </ScrollView>