diff --git a/misp_stix_converter/stix2misp/converters/stix2_indicator_converter.py b/misp_stix_converter/stix2misp/converters/stix2_indicator_converter.py
index 94a597f..3e79544 100644
--- a/misp_stix_converter/stix2misp/converters/stix2_indicator_converter.py
+++ b/misp_stix_converter/stix2misp/converters/stix2_indicator_converter.py
@@ -1106,13 +1106,13 @@ def _parse_yara_pattern(self, indicator: _INDICATOR_TYPING):
 
     def _unknown_pattern_mapping_warning(
             self, indicator_id: str, pattern_types: GeneratorType):
-        self._add_warning(
+        self.main_parser._add_warning(
             f'Unable to map pattern from the Indicator with id {indicator_id}, '
             f"containing the following types: {', '.join(pattern_types)}"
         )
 
     def _unmapped_pattern_warning(self, indicator_id: str, feature: str):
-        self._add_warning(
+        self.main_parser._add_warning(
             'Unmapped pattern part in indicator with id '
             f'{indicator_id}: {feature}'
         )
diff --git a/misp_stix_converter/stix2misp/stix2_to_misp.py b/misp_stix_converter/stix2misp/stix2_to_misp.py
index 30bb8b9..5c9865f 100644
--- a/misp_stix_converter/stix2misp/stix2_to_misp.py
+++ b/misp_stix_converter/stix2misp/stix2_to_misp.py
@@ -734,7 +734,7 @@ def _parse_analyst_note(note: Note) -> dict:
         if hasattr(note, 'abstract'):
             note_dict['comment'] = note.abstract
         if hasattr(note, 'authors'):
-            note_dict['authors'] = note.authors
+            note_dict['authors'] = ', '.join(note.authors)
         if hasattr(note, 'lang'):
             note_dict['language'] = note.lang
         return note_dict
@@ -746,7 +746,7 @@ def _parse_analyst_opinion(opinion: Opinion) -> dict:
             'created': opinion.created, 'modified': opinion.modified
         }
         if hasattr(opinion, 'authors'):
-            opinion_dict['authors'] = opinion.authors
+            opinion_dict['authors'] = ', '.join(opinion.authors)
         return opinion_dict
 
     ############################################################################