Same for me. I was only able to read around 50% of threads last week. Now I can see all but two really stubborn ones, links below:
https://www.flyertalk.com/forum/aege...-new-post.html
Please report your Star Alliance award redemption experiences
I upgraded my browser (Chrome) to the latest version, cleared cache etc. and also tried with Firefox and Brave with no luck. Those two threads seem corrupted or incompatible with some software update on the FT side.
EDIT: I can actually read them with Microsoft Edge!
More Edit: I can also view them if I open in an Incognito window in Chrome, but I don't know if that causes any content to be missing.