Hi there, really sorry to hear about this problem. Can you use the Help & Support -> Message support function to submit a ticket with the problem you are experiencing? We will make sure to look into it and fix it.
In fact, looking for these links, I now found an official Notion reply from 4 years ago in one of these threads[4]: "should keep you logged in for 90 days per device".
This had me find [5]: "Notion has a default session duration of 90 days. This means all users automatically get logged out if they have stayed logged in for 90 consecutive days.".
If logging out any session after 90 days is the expected behavior, this would completely explain the behavior in my case. Can you confirm that this is happening for all accounts?
[0]: https://www.reddit.com/r/Notion/comments/brcy5m/random_logou...
[1]: https://www.reddit.com/r/Notion/comments/vi8c9f/constantly_g...
[2]: https://www.reddit.com/r/Notion/comments/194xw0m/anyone_else...
[3]: https://www.reddit.com/r/Notion/comments/dsi5jo/login_proces...
[4]: https://www.reddit.com/r/Notion/comments/dsi5jo/login_proces...