Extend modular.html.twig in child Quark theme

Hi,

I'm trying to add some code in modular.html.twig - {% block body %} - in my child theme.
But when I add the modular.html.twig with {% extends 'modular.html.twig' %} it results in:
Fatal error : Allowed memory size of 536870912 bytes exhausted...

For what I could gather, this results in a loop hence the memory exhausted.

Is it possible to extend a template from parent to child theme? Or do I have to copy the full template to the child theme?

Cheers!
Pedro

Is it safe to say that there is no way to extend the template directly from parent theme?
For now i copied modular.html.twig to child, but this undermines the inheritence principle, I think.

Still searching...