It works fine for me, give me link of the video that the icon doesn't appear under so I can see from where the problem...
Here is proof that it still works for me: https://i.imgur.com/UGb33ef.png


Edit:

The post you shared isn't a video, it's a photo the extension only works with videos now.
Here is a screenshot for a video on the same channel. you can try with this link if the icon doesn't show up tell me to see if there is a problem with it.

screenshot: https://i.imgur.com/oN9GSwy.png
link: https://www.threads.net/@hoon_kim/post/C0vORJOreCh