SDCs which extend another SDC do not save when used in paragraph

Found out that it works if I remove {{ attributes.addClass(classes) }} as seen here: https://www.lullabot.com/articles/getting-single-directory-components-dr... it then works.

My setup looks like this:

SDC:LINK

{% set classes = [
  'link'
] %}
<a {{ attributes.addClass(classes) }} target="{{ target }}" href="{{ href }}">
  {% block link_text %}{{ text }}{% endblock %}
</a>

SDC:LINKBUTTON

{% extends 'sdc:link' %}
{% set attributes = attributes.addClass('button') %}

As soon as I remove {{ attributes.addClass(classes) }} it works. Any ideas why this is happening highly appreciated.

I think this is due to how extends works in Twig.

https://twig.symfony.com/doc/3.x/