Github user aljoscha commented on the issue:
https://github.com/apache/flink/pull/5032
I think catching the `ClassCastException` is not the proper way to fix
this. This might be masking other (real) bugs that lead to
`ClassCastExceptions`. We should detect whether the wrong type is used for
accessing a state that was already registered in the part of the code that does
this, probably in `AbstractKeyedStateBackend`.---
