I have exactly the same problem. I'm on MacOS using "&scale=2000" at the end of the embedded code of the Restream Chat. So the problem it's the way OBS for Mac renders any content in the browser source. Just for seeing the chat I had to scale it but this makes the normal emojis distorted. I hope someone from OBS or Restream can fix this bug soon or maybe a temporary solution.
Here a snapshot... you can see that the emoji also affects the Twitch emote putting visible the last character of the Twith emote.
When I don't use emojis everything runs well.