convert: Avoid multiple reads on enum lookup members.

Author: heinezen

openage/convert/value_object/read/genie_structure.py

@@ -1,4 +1,4 @@
-# Copyright 2014-2024 the openage authors. See copying.md for legal info.
+# Copyright 2014-2025 the openage authors. See copying.md for legal info.
 
 # TODO pylint: disable=C,R
 
@@ -587,7 +587,7 @@ def _read_primitive(
                     generated_value_members.append(gen_member)
 
             # run entry hook for non-primitive members
-            if is_custom_member:
+            if isinstance(var_type, ContinueReadMember) and is_custom_member:
                 result = var_type.entry_hook(result)
 
                 if result == ContinueReadMember.result.ABORT: