Thanks for your feedback! I have just released a new version that provides a temporary solution to the YouTube comments issue. Once the comments are loaded, you can right-click on the text and manually rescan for emojis.

In case you're interested, the issue you mentioned is caused by two reasons:

1. YouTube does not load comments until after they are scrolled into view, long after this add-on has scanned the page. I don't have a good solution for efficiently listening to all page changes, but will look more into it in the future.

2. Twitter.com discards emojis and replaces them with embedded images. The good thing is that they do include the translation in the mouseover tooltip on twitter.com. On TweetDeck, the emojis are similarly replaced, but without the tooltip. I can see a way of salvaging that information, but it will have to be a site-specific solution.