When a streams application has little traffic, then it is possible that consumer purging would delete
even the last message sent by a producer (i.e., all the messages sent by
this producer have been consumed and committed), and as a result, the broker
would delete that producer's ID. The next time when this producer tries to
send, it will get this UNKNOWN_PRODUCER_ID error code, but in this case,
this error is retriable: the producer would just get a new producer id and
retries, and then this time it will succeed.
Possible fixes could be on the broker side, i.e., delaying the deletion of the produderIDs for a more extended period or on the streams side developing a more conservative approach to deleting offsets from repartition topics