custom post type WYSIWG removes paragraphs when displayed

I have a WordPress 5.2.3 instance that is multilingual with the help of the qtranslate-x plugin. I created a custom post type with a translatable WYSIWG field. The visual WYSIWG editor generally works, but when I display the content of the field on a page, the paragraphs are removed.

This is how it looks like in the editor:

This is how the page is rendered (direct link: https://crossroads-festival.org/de/film/your-turn):

As you can see, the paragraphs are lost when the field is displayed.

Interestingly, if I do the editing in HTML by using the text mode of the WYSIWG editor, the formatting does not get lost. However, this is not a solution, since my client wants to work with the visual editor.

I use the following plugins related to custom fields and translations. All are updated:

• Advanced Custom Fields
• Advanced Custom Fields: qTranslate
• Custom Post Type UI
• qTranslate slug
• qTranslate-X

I don't know how or where to exactly fix this issue. Any hints are appreciated.