Is this still a problem for you?
I don't have a Microsoft environment with which to test, but my Firefox view of content at the given URL https://forums.macrumors.com/forums/alternatives-to-ios-and-ios-devices.157 – note, the absence of a trailing / – does not include the word Expires so my first guess would be, an intermittent problem involving your browser's use of cookies.
Thanks.
I'm not familiar with the browser that's in your screenshot. Is it Edge?
Whatever it is, have you followed Microsoft advice on dealing with cookies?