Hi Firmin,
Firmin Martin writes:
> In the agenda buffer, I've called the `org-set-effort` function
> with the `e` key, and input "-" which is malformed. I did receive
> an error `Invalid duration format: "-"`, but the "-" has still been
> written in the entry as an effort property.
>
> As a cons
Remember to cover the basics, that is, what you expected to happen and
what in fact did happen. You don't know how to make a good report? See
https://orgmode.org/manual/Feedback.html#Feedback
Your bug report will be posted to the Org mailing list.