MediaWiki Semantic Template: Property "" (as page type) with input value contains invalid characters or is incomplete can cause unexpected results

Question

Thanks to this answer I've created a template which mix a visual representation and populates a semantic one.

I've used the template in a page but the last part doesn't work and returns the following message.

Property "" (as page type) with input value "psicologia|governo|politica|lavoro|+sep=|" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process.

The template:

[{{{url}}} {{{title}}}] - {{{categories}}} 
{{#subobject:
|url = {{{url}}}
|title = {{{title}}}
|@category={{{categories}}}
}}

The desired behaviour:

{{#subobject:
|url = https://www.instagram.com/p/CXeE2j-NT6s/
|title = Bullismo: proposta una legge in Francia per punirlo penalmente. Si rischia anche il carcere
|@category=bullismo|violenza|leggi|punizioni|+sep=|
}}

Answer 1

You cannot use | as a separator, it will not recognize it as a separator, try a comma, a hyphen or something that you generally don't use in Mediawiki coding