Its a change we made for Mastodon to be compatible with Lemmy. So it was part of the v0.14 release, but we forgot to mention it in the changelog. Without it, Mastodon wont be able to fetch Lemmy posts/communities etc when you search the url on Mastodon. But that is working fine with your instance.

There is something wrong with your inbox though, meaning activities sent to your instance dont arrive. Make sure you also have this line (with correct port). Ansible takes care of that automatically btw. If the nginx config looks fine, try to capture some logs on your instance while sending an activity (eg create comment or vote) to baraza, using docker-compose logs -f lemmy -t 100.