diff --git a/capella2polarion/converters/data_session.py b/capella2polarion/converters/data_session.py
index 46ef2914..5b9e6282 100644
--- a/capella2polarion/converters/data_session.py
+++ b/capella2polarion/converters/data_session.py
@@ -20,6 +20,7 @@ class ConverterData:
     capella_element: diagram.Diagram | common.GenericElement
     work_item: dm.CapellaWorkItem | None = None
     description_references: list[str] = dataclasses.field(default_factory=list)
+    errors: set[str] = dataclasses.field(default_factory=set)
 
 
 ConverterSession = dict[str, ConverterData]
diff --git a/capella2polarion/converters/element_converter.py b/capella2polarion/converters/element_converter.py
index af7a492a..70df813a 100644
--- a/capella2polarion/converters/element_converter.py
+++ b/capella2polarion/converters/element_converter.py
@@ -116,7 +116,6 @@ def __init__(
         self.capella_polarion_mapping = capella_polarion_mapping
         self.converter_session = converter_session
         self.generate_attachments = generate_attachments
-        self.non_existing: dict[str, set[str]] = {}
 
     def serialize_all(self) -> list[data_models.CapellaWorkItem]:
         """Serialize all items of the converter_session."""
@@ -142,16 +141,12 @@ def serialize(self, uuid: str) -> data_models.CapellaWorkItem | None:
                 ] = getattr(self, f"_{converter}")
                 serializer(converter_data, **params)
             except Exception as error:
-                logger.error(
-                    "Serializing model element %r failed. %s",
-                    uuid,
-                    error.args[0],
-                )
+                converter_data.errors.add(error.args[0])
                 converter_data.work_item = None
                 return None  # Force to not overwrite on failure
         assert converter_data.work_item is not None
-        for finding in self.non_existing.get(uuid, []):
-            logger.warning("Found %s (%r)", finding, uuid)
+        for finding in converter_data.errors:
+            logger.warning("Serialization failed: %s (%r).", finding, uuid)
         return converter_data.work_item
 
     # General helper functions
@@ -295,10 +290,9 @@ def repair_images(node: etree._Element) -> None:
                     node.attrib["src"] = f"workitemimg:{file_name}"
 
             except FileNotFoundError:
-                logger.error(
-                    "Inline image can't be found from %r for %r",
-                    file_path,
-                    obj._short_repr_(),
+                self.converter_session[obj.uuid].errors.add(
+                    f"Inline image can't be found from {file_path!r} "
+                    f"for {obj._short_repr_()!r}"
                 )
 
         repaired_markup = chelpers.process_html_fragments(
@@ -321,16 +315,16 @@ def _replace_markup(
         try:
             self.model.by_uuid(uuid)
         except KeyError:
-            self.non_existing.setdefault(uuid, set()).add(
-                "reference in description"
+            self.converter_session[uuid].errors.add(
+                "Non-existing model element referenced in description"
             )
             return strike_through(match.group(default_group))
         if pid := self.capella_polarion_mapping.get_work_item_id(uuid):
             referenced_uuids.append(uuid)
             return POLARION_WORK_ITEM_URL.format(pid=pid)
 
-        self.non_existing.setdefault(uuid, set()).add(
-            "reference in description"
+        self.converter_session[uuid].errors.add(
+            "Non-existing work item referenced in description"
         )
         return match.group(default_group)
 
@@ -341,8 +335,8 @@ def _get_requirement_types_text(
         type_texts = collections.defaultdict(list)
         for req in getattr(obj, "requirements", []):
             if req is None:
-                self.non_existing.setdefault(obj.uuid, set()).add(
-                    "RequirementsRelation with broken target"
+                self.converter_session[obj.uuid].errors.add(
+                    "Found RequirementsRelation with broken target"
                 )
                 continue
 
@@ -350,8 +344,8 @@ def _get_requirement_types_text(
                 identifier = (
                     req.long_name or req.name or req.summary or req.uuid
                 )
-                self.non_existing.setdefault(obj.uuid, set()).add(
-                    f"Requirement without text or type on {identifier!r}"
+                self.converter_session[obj.uuid].errors.add(
+                    f"Found Requirement without text or type on {identifier!r}"
                 )
                 continue