Translation:We were speaking loudly while they were telling stories.
"We were speaking loudly while they were telling" should not be a correct or suggested solution. It's grammatically incorrect in English - you need to 'tell somebody (something).
There are multiple problems with the "correct solution"
povesteau = narrating, recounting
The usage of the word telling in the construct of the "correct solution" requires an object.
The Romanian sentence does not mention the word "stories", so the narration could be of anything
you're right... my comment was about Duo's second "correct solution" not shown above... should have been more explicit :-)
For this DL translation, would "...they were telling/used to tell stories = "ei spuneau povești"?