Fix: Product Localizer now checks if a value is filled, or, not to show the fallback

src/Catalog/Support/ProductDocumentLocalizer.php

@@ -51,7 +51,15 @@ class ProductDocumentLocalizer
         $availableLocales = $this->languages->availableLocales();
 
         foreach ($this->translatedAttributeHandles() as $handle) {
-            $product[$handle] = $product[$handle.'_'.$locale] ?? $product[$handle.'_'.$fallbackLocale] ?? null;
+            // filled(), not ?? - a translated attribute saved blank for
+            // the current locale still has that {handle}_{locale} key in
+            // the document, just set to '' rather than absent. ?? only
+            // falls back on a missing/null key, so it kept the empty
+            // string instead of falling through to a locale that actually
+            // has content.
+            $product[$handle] = filled($product[$handle.'_'.$locale] ?? null)
+                ? $product[$handle.'_'.$locale]
+                : ($product[$handle.'_'.$fallbackLocale] ?? null);
 
             foreach ($availableLocales as $availableLocale) {
                 unset($product[$handle.'_'.$availableLocale]);