I am not sure I would say something is broken here. When a post contains a link, the translation contains the same link.
Example:
Post written in English:
Have you heard of Discourse? It's a great forum software. See
https://discourse.org
Translation to German:
Hast du schon von Discourse gehört? Es ist eine tolle Forumssoftware. Schau mal auf:
https://discourse.org
Where do you expect the translation of the content inside the onebox to be saved and how should it be entered during manual translation?
The customizable, scalable community platform powering over 22,000 communities. Create knowledge through conversation.
Is not part of my post