La sintaxis de FreeMarker no es válida.

The following has evaluated to null or missing:
==> parentCategory.id [in template "template_id" at line 189, column 201]

----
Tip: It's the step after the last dot that caused this error, not those before it.
----
Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use [#if myOptionalVar??]when-present[#else]when-missing[/#if]. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
----

----
FTL stack trace ("~" means nesting-related):
- Failed at: ${parentCategory.id} [in template "template_id" at line 189, column 199]
----