Github user aljoscha commented on the issue:
https://github.com/apache/flink/pull/5545
Yes, no source can use keyed state. ð But the `StateAssignmentOperation`
will still fail a restore if the `maxParallelism` of an operator changes. Maybe
@StefanRRichter can chime in on that but I think we need to at least touch
those parts.---
