state reset(lost) on TM recovery

[Alexey Trenikhun]

Hello,

I'm using Flink 1.11.3, state backend is rocksdn. I have streaming job which 
reads from Kafka, transforms data and output into Kafka, one of processing 
nodes is KeyedCoProcessFunction with ValueState:

  1.  generated some input data, I see in log that state.update() is called and 
subsequent state.value() return not null
  2.  wait for checkpoint
  3.  restart taskmanager
  4.  state.value() returns null

I've tried to change backend from rocksdb to filesystem - same result, after 
taskmanager restart state.value() returns null

Any ideas, what could cause resetting state to null?

Thanks,
Alexey