Flex objects -> render as Markdown

Hello,

i created a custom flex-object: “news” with custom fields. When i put Markdown in the fields the content is displayed in plain text, when i view the entries on i.e. website/flex-objects/directory:news.

I added the markdown twig:

{% markdown %}
{% endmarkdown %}

in my default.html.twig of my news flex-object, but it didn´t work.

Can i use Markdown with flex-objects, or is the save to json the problem?

Thank you in advance