GitLab Deauthenticates User Apparently for No Reason and Without Notification

Sometimes, I will be forcibly logged out of GitLab.

This happens very frequently, but in batches. For example, I may not be logged out of GitLab at all for a week or so, and then for a few days, I will be logged out multiple times per day.

The least intrusive times that this happens, I am not actively using GitLab. I will return to the site and find that my login is invalid.

However, more common - and much worse - is when I am actively using the site.
An example:

1. I am logged in
2. I begin an MR review
3. I leave a comment or do some other action like leaving a reaction emoji
4. I continue the review - fewer than 5 minutes elapse
5. I try to leave another comment or a reaction - an error occurs, which doesn't inform me that I've been logged out.
   • Because I have dozens of experiences with this, I know to refresh the page, after which I see that the header bar is the "Log in / Sign Up" button instead of my profile image
   • However, none of the error messages indicate that I've been logged out, they just say that submitting my comment (etc.) has failed.
6. I log back in
7. Fortunately, comments are cached locally, etc. so I can pick right back up

My memory isn't great, but I recall this happening once while I was in the middle of submitting an MR, and that is not cached, causing me to lose the entire MR description and other metadata.

Why am I being logged out of GitLab regularly and frequently?