It has happened for the duration of the server. I installed the server back in May I believe from your site from docker image and updated it only the other day and still the same issue, never been able to have quotes working.
I just presumed they were not implemented as this was the case with discord when we used that some years ago but reading around the other day I realized this is a bug rather than the norm as others reported quotes working fine and the website docs too.
In the info tab it says version 3.0.12 now but sorry I don’t remember what it was before update, however I know the issue persists regardless of the version I have used.
No not group dm. We have both public and private channels/groups and irrespective of which the behavior is the same in both.