diff --git a/odoo/addons/base/models/ir_actions_report.py b/odoo/addons/base/models/ir_actions_report.py
index aafbe9ae402..e2d194303b3 100644
--- a/odoo/addons/base/models/ir_actions_report.py
+++ b/odoo/addons/base/models/ir_actions_report.py
@@ -717,9 +717,15 @@ class IrActionsReport(models.Model):
 
             # Split the pdf for each record using the PDF outlines.
 
+            html_ids_wo_none = [x for x in html_ids if x]
             if len(res_ids_wo_stream) == 1:
                 # Only one record: append the whole PDF.
                 collected_streams[res_ids_wo_stream[0]]['stream'] = pdf_content_stream
+            elif not html_ids_wo_none:
+                # When rendering some html without a one to one match between each res_id and a document
+                # 'html_ids' contains some 'None' values. In that case, there is nothing to split and the content
+                # can be returned directly.
+                collected_streams[False] = {'stream': pdf_content_stream}
             else:
                 # In case of multiple docs, we need to split the pdf according the records.
                 # To do so, we split the pdf based on top outlines computed by wkhtmltopdf.
@@ -808,7 +814,7 @@ class IrActionsReport(models.Model):
                     _logger.info("The PDF documents %r are now saved in the database", attachment_names)
 
         # Merge all streams together for a single record.
-        streams_to_merge = [x['stream'] for x in collected_streams.values()]
+        streams_to_merge = [x['stream'] for x in collected_streams.values() if x['stream']]
         if len(streams_to_merge) == 1:
             pdf_content = streams_to_merge[0].getvalue()
         else: