Not quite _always_. There were some documented caveats... the one I hit before was:
Read nonexistent key, followed by a write of that same key, and then a subsequent read could return a stale read saying it didn’t exist. (even though it had just been written for the first time.)
Anyway I am glad to see these gaps and caveats have been closed.
After a write, you would _always_ be able to read the key you just wrote.
After an update, you could get a stale copy of the key if your subsequent read hit a different server.