Github user aljoscha commented on the issue:
https://github.com/apache/flink/pull/5732
@StephanEwen Yes, I think this should go into 1.5.0 because it fixes
potential (and real) problems. And yes, I wasn't suggesting to remove
`initializeSerializerUnlessSet(ExecutionConfig)` now, but it seemed like a good
place to mention it. ð ---
