A new Kafka consumer gets created for every batch

I have a fairly simple piece of code that reads from Kafka, applies some transformations - including applying a UDF - and writes the result to the console. Every time a batch is created, a new consumer is created (and not closed), eventually leading to a "too many open files" error.

I created a test case, with the code available here: https://github.com/aseigneurin/spark-kafka-issue

To reproduce:

1. Start Kafka and create a topic called "persons"
2. Run "Producer" to generate data
3. Run "Consumer"

I am attaching the log where you can see a new consumer being initialized between every batch.

Please note this issue does not appear with Spark 2.2.2, and it does not appear either when I don't apply the UDF.

I am suspecting - although I did go far enough to confirm - that this issue is related to the improvement made in SPARK-23623.