diff --git a/.gitignore b/.gitignore
index b07cd61..182c480 100644
--- a/.gitignore
+++ b/.gitignore
@@ -73,6 +73,9 @@ target/
 # Jupyter Notebook
 .ipynb_checkpoints
 
+# PyCharm
+.idea
+
 # pyenv
 .python-version
 
diff --git a/webauthn/helpers/structs.py b/webauthn/helpers/structs.py
index 5bada95..a186349 100644
--- a/webauthn/helpers/structs.py
+++ b/webauthn/helpers/structs.py
@@ -85,13 +85,14 @@ def _pydantic_v2_validate_bytes_fields(
             """
             field = cls.model_fields[info.field_name]  # type: ignore[attr-defined]
 
-            if field.annotation != bytes:
+            # UserHandle is defined as Optional[bytes] which is represented as:
+            # field.annotation = typing.Optional[bytes]. So we handle that explicitly here.
+            if field.annotation != bytes and info.field_name != 'user_handle':  # type: ignore[attr-defined]
                 return v
 
-            if isinstance(v, str):
-                # NOTE:
-                # Ideally we should only do this when info.mode == "json", but
-                # that does not work when using the deprecated parse_raw method
+            # base64 encoding is the standard used when serializing bytes for JSON
+            # requests. For direct python the field value is assumed to already be bytes.
+            if isinstance(v, str) and info.mode == "json":  # type: ignore[attr-defined]
                 return base64url_to_bytes(v)
 
             return _to_bytes(v)