Diễn đàn hỗ trợ Firefox

When photos, videos, or websites are linked on a FB comment, it used to display a thumbnail preview below the comment. Now it just shows the link. On mobile, the preview appears. So I'm thinking a setting got changed on the desktop version.

Does anyone know what the issue is and how to correct?

If I have a chat open or the video has a chat replay instead of showing the chat it pops up a mini browser instead. It constantly duplicates itself too, causing the video to be unwatchable with the sound constantly repeating. I've seen a couple other people with this issue but have been unable to find a solution.