Sounds like JavaScript. Posts on the recent sidebar are different, in that they launch a new standalone page, rather than using JS to request post text and display it. Also, sounds like you're talking about root posts; what about replies?

You've described your setup as, uh, how shall I say it, vintage? Any change on that front? Just a fact of life that it becomes harder and harder to support older computers and software as time goes on. Do you have a smartphone you can try for comparison?

Nothing's changed on the Zone in a long time (sad to say). If others report no change, logically I have to point the accusatory finger at your computer, software, or both. Even if you believe nothing's changed, the success of the many outweighs the problems of the few, in the realm of diagnosis.

Please fill me on your present setup, and maybe we can go from there. If your computer will support, it may be a different web browser will bring relief.