I presume you're not a native English speaker and you have Twitter set up in another language other than English, like French or German.
TLD "reads" the text on the page in order to find the tweets and the links. If the page is not translated to English, it won't find them. I discovered this unforeseen behavior after you posted the review.
I started working on a solution and will update the add-on soon.
Alin
Edit 2021: Haha! I fixed it back in 2019. I'm glad you found out, in the end.
