When you access a discussion page, most of the time only the form for writing a new message appears. You have to refresh the page to see the messages appear.
There must be a problem with the cache management …
Yup I can clearly replicate this too. I can see there’s an open issue on this Reloading page is often needed (#1688) · Tickets · Kaihuri / Mobilizon · GitLab, I might try and take a look at it!