Our topic is created with retention period of 3 days. Topic has four partitions. Broker level default is 12 hour.
Some partition's segment get deleted even before 3 days. Logs show that segment is marked for deletion because it exceeded 43200000ms = 12 hours.
"INFO Found deletable segments with base offsets  due to retention time 43200000ms breach (kafka.log.Log)"
This does not happen for all partitions. Post full cluster bounce , partitions facing this issue change.
Topic config :
Topic:TOPICNAME PartitionCount:4 ReplicationFactor:2 Configs:retention.ms=259200000,segment.ms=43200000
Topic: TOPICNAME Partition: 0 Leader: 1 Replicas: 1,8 Isr: 1,8
Topic: TOPICNAME Partition: 1 Leader: 2 Replicas: 2,9 Isr: 9,2
Topic: TOPICNAME Partition: 2 Leader: 3 Replicas: 3,1 Isr: 1,3
Topic: TOPICNAME Partition: 3 Leader: 4 Replicas: 4,2 Isr: 4,2
Broker config :