Could you provide some info on when is this error happening?
From what I see you are using the heap or fs state backend and you are failing to read the state back when restoring from a failure. The failure can be unrelated to this, but it could be useful if you could check the task manager logs to see why the failure happens and if there are any exceptions when checkpointing for example.
Also could you share the code for your objects (what you are serializing)? Just to cover some cases.
Which Flink version you are using? 1.2 What is your job doing (e.g. operators that you are using)? ProcessFunction to determine if event is late change event time to current & then window Which operator throws this exception? i will have to dig it further Which state-backend are you using? mysql.