Profile vs. conversation
If you can still view their Facebook profile but messages fail, that points to Messenger-specific settings, not a full Facebook block.
Ignored and restricted chats
'Ignore messages' and 'Restrict' move your chat out of their inbox and stop them seeing read status, but they don't block you. Your messages may look unread forever.
Limitations on Messenger
- Messenger and Facebook blocking are independent.
- Ignored and restricted conversations hide activity without blocking.
- Notices are user-reported here; we can't see your screen.