To group operations by second. I found expected behaviour in HZ mailing group:

HZ delays these store operations by grouping them to relative to their registration times at the goal of bulk execution of all operations within the "same second". This "same second" thingy is determined by a function of write delay seconds & registration time.

if map.put and map.replace are inside the same "second group" HZ executes them as bulk operations and picks the last op. In my example this is only one INSERT, otherwise you can see one INSERT and one UPDATE respectively.

https://groups.google.com/forum/#!msg/hazelcast/LOijWuWM15I/b0nLfb2htFoJ


Actually. I don't really happy about this new strategy in HZ 3, and I want to discuss that,
but I assume data corruption need to be fixed quick