Wow, thank you very much, that was exactly the answer to the question.

wtf are you doing using this module?!

You are right, I started using it more than ten years ago and did not really look at the warning, constant amateur behaviour.

No, XML::Simple is not an XML parser.

Something I did not realize

local $XML::Simple::PREFERRED_PARSER = 'XML::Parser';

Defining the Parser leads to the expected behaviour and solves the task.

I will have to try to move on to something else and will start with XML::Rules. Nevertheless the not recommended module works as it should with the above.