Check on what's the relay this account is publishing to.
The easiest way is, to look for the account on https://njump.me/npub18qd5edjc0dscrftdnjgxe8986ztt66nmpmrnyc7tlhlrvzx5p4yqu456u9 there's a "publishing to" title.
Or if you're on Amethysts, go to their profile, slide the stuff menus to the left and chose relays.
You need to read from those relays.
I'm not exactly sure how the relay gets their posts. Maybe we just need to give them a bit more time. Or nostr:npub1q3sle0kvfsehgsuexttt3ugjd8xdklxfwwkh559wxckmzddywnws6cd26p can tell exactly how those works.