[Risolto] Content in Guthenberg does not get translated

Background of the issue:
I am using Elementor, but my client is making his "news" posts in the normal Guthenberg builder. The original content is in English. I have translated the website to Swedish and Spanish.

Symptoms:
When I translate the posts and save, the content reverts back to English on both the Swedish and Spanish versions.

Questions:
Why does the translated content revert back to English after saving?
How can I ensure that translations are saved correctly in WPML?