Only generate proxy properties once for related syncable fields

aleksis/core/mixins.py

@@ -288,6 +288,7 @@ class ExtensibleModel(models.Model, metaclass=_ExtensibleModelBase):
                     name = f"_{field.name}__{subfield.name}"
                     verbose_name = f"{field.verbose_name} -> {subfield.verbose_name}"
 
+                    if not hasattr(cls, name):
                         # Add proxy properties to handle access to related model
                         def getter(self):
                             if hasattr(self, field.name):