Size of FileRecords has been truncated during write

Hello
We are running Apache Kafka 3.9.0 in z/OS. We noticed following exception/warning in Kafka logs (it comes frequently, causing space issues due to the huge logs):

Ý2026-03-26 23:15:56,003¨ WARN ÝSocketServer listenerType=ZK_BROKER, nodeId=1¨ Unexpected error from /127.0.0.1 (channelId=127.0.0.1:9092-127.0.0.1:50290-10); closing connection (org.apache.kafka.common.network.Selector)
org.apache.kafka.common.KafkaException: Size of FileRecords /global/kafka/SYS/kafka-logs/xxxx.infeed.private.v1-0/00000000000000000000.log has been truncated during write: old size 194, new size 97
.at org.apache.kafka.common.record.FileRecords.writeTo(FileRecords.java:298)
.at org.apache.kafka.common.record.DefaultRecordsSend.writeTo(DefaultRecordsSend.java:34)
.at org.apache.kafka.common.record.RecordsSend.writeTo(RecordsSend.java:50)
.at org.apache.kafka.common.record.MultiRecordsSend.writeTo(MultiRecordsSend.java:93)
.at org.apache.kafka.common.network.NetworkSend.writeTo(NetworkSend.java:45)
.at org.apache.kafka.common.network.KafkaChannel.write(KafkaChannel.java:440)
.at org.apache.kafka.common.network.Selector.write(Selector.java:664)
.at org.apache.kafka.common.network.Selector.attemptWrite(Selector.java:657)
.at org.apache.kafka.common.network.Selector.pollSelectionKeys(Selector.java:613)
.at org.apache.kafka.common.network.Selector.poll(Selector.java:501)
.at kafka.network.Processor.poll(SocketServer.scala:1110)
.at kafka.network.Processor.run(SocketServer.scala:1014)
.at java.base/java.lang.Thread.run(Thread.java:853)

It's always for the same file 00000000000000000000.log, the size differs, the number of truncated bytes differs, for example:
old size 194, new size 97
old size 8397, new size 8300
old size 35270, new size 34617

What is causing the truncation? How can we fix it?

Regards
Dorota


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