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.
like if you had tried to read a non-existent key, then wrote to it, it might continue to appear to not exist for a minute?