This post seems to have a collapsible (JSON) entry, but Fig does not show it:
(It works on the web)
Looks like it works for me.
Maybe if you can specify if there is anything different with how it doesn’t work for you.
It now works for me as well (earlier I could only see the headline, no matter whether I opened/closed it).
Maybe a backend issue on their side earlier today?
Anyway, case closed!