diff --git a/python/plugins/processing/core/Processing.py b/python/plugins/processing/core/Processing.py
index 06289b325c8..db17c63e898 100644
--- a/python/plugins/processing/core/Processing.py
+++ b/python/plugins/processing/core/Processing.py
@@ -162,6 +162,9 @@ class Processing(object):
             else:
                 # auto convert layer references in results to map layers
                 for out in alg.outputDefinitions():
+                    if out.name() not in results:
+                        continue
+
                     if isinstance(out, (QgsProcessingOutputVectorLayer, QgsProcessingOutputRasterLayer, QgsProcessingOutputMapLayer)):
                         result = results[out.name()]
                         if not isinstance(result, QgsMapLayer):
diff --git a/python/plugins/processing/tests/testdata/custom/circular_strings.gpkg b/python/plugins/processing/tests/testdata/custom/circular_strings.gpkg
index 3f82c62ed55..6c42ec2c58d 100644
Binary files a/python/plugins/processing/tests/testdata/custom/circular_strings.gpkg and b/python/plugins/processing/tests/testdata/custom/circular_strings.gpkg differ