diff --git a/lighting_export_xlsx/models/product_attachment.py b/lighting_export_xlsx/models/product_attachment.py
index a75c94eb..fe788b12 100644
--- a/lighting_export_xlsx/models/product_attachment.py
+++ b/lighting_export_xlsx/models/product_attachment.py
@@ -17,7 +17,11 @@ def export_xlsx(self, template_id=None):
             if prod_attachment_ids.mapped("attachment_id"):
                 non_public = prod_attachment_ids.filtered(lambda x: not x.public)
                 if non_public:
-                    non_public.sudo().write({"public": True})
+                    ids_list = self.env.context.get("non_public_attachment_ids")
+                    if ids_list is not None:
+                        ids_list.extend(non_public.ids)
+                    else:
+                        non_public.sudo().write({"public": True})
                 for pa in prod_attachment_ids:
                     res.append(
                         OrderedDict(
diff --git a/lighting_export_xlsx/report/export_product_xlsx.py b/lighting_export_xlsx/report/export_product_xlsx.py
index af393e8a..54bb414c 100644
--- a/lighting_export_xlsx/report/export_product_xlsx.py
+++ b/lighting_export_xlsx/report/export_product_xlsx.py
@@ -56,7 +56,10 @@ def generate_xlsx_report_ctx(self, workbook, data, objects):  # noqa: C901
         self._check_duplicate_labels(header, template_id)
 
         # generate data and gather header data
-        objects_ld = self._generate_products(header, objects.ids, template_id)
+        non_public_ids = []
+        objects_ld = self.with_context(
+            non_public_attachment_ids=non_public_ids
+        )._generate_products(header, objects.ids, template_id)
 
         # generate xlsx headers according to data
         xlsx_header = []
@@ -108,6 +111,13 @@ def generate_xlsx_report_ctx(self, workbook, data, objects):  # noqa: C901
                         col += 1
             row += 1
 
+        # make exported attachments public (single write at the end to avoid
+        # concurrent access issues during batch processing)
+        if non_public_ids:
+            self.env["lighting.attachment"].sudo().browse(non_public_ids).write(
+                {"public": True}
+            )
+
     def _check_duplicate_labels(self, header, template_id):
         seen_labels = {}
         for field, meta in header: