Just created key can be omitted

[VadimPushtaev]

If you happen to create a key on some node X and immediately do recursive read on another node Y, it's entirely possible for the key not to be there.

https://github.com/jplana/python-etcd/blob/b227f496c038b2b856c4d76c9525b3547e5c8dc4/src/etcd/lock.py#L176

[VadimPushtaev]

As with all distributed systems, it is impossible for etcd to ensure strict consistency. etcd does not guarantee that it will return to a read the “most recent” value (as measured by a wall clock when a request is completed) available on any cluster member.

https://coreos.com/etcd/docs/latest/learning/api_guarantees.html#guarantees-provided