I think this is happens when the topic and the topic author is deleted but the topic link is shared and still available on an other topic so that is still exist and clickable. When you click it this page comes. I believe there should be some errors related with this in /logs.
Edit: Now I cannot reproduce it but It happened once on our forum. A new userA create a topic, userB share that topic in other topic. Than userA is delete himself so the previously created topic is also deleted. After this when click the link what userB shared get this error page. But maybe it caused by a plugin for us
My users are reporting that it happens with basically random interactions on the site (desktop only).
Similar things happen to multiple functions. Clicking the top right avatar, pressing the number left to the heart to see who liked something, leaving likes (this is rare), viewing the leaderboard.
Thanks for the tip about the /logs page, I forgot that exists. I have a custom discord plugin I’m running and it seems most of the errors on the page are related to that. I will attempt to debug it soon, if the problem in the OP exists after that I’ll bump this topic. Thanks again