Kafka can not delete old logs for some portion

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Hi,everyone

I am using kafka 2.3.1,Following are my retention policy attributes :

log.retention.hours=168
log.segment.bytes=1073741824
log.retention.check.interval.ms=300000

When kafka cluster running a period,I found that  Kafka not deleting old logs after 7 days. 

Here is whole config for my kafka cluster:
log.retention.hours=168
log.segment.bytes=1073741824
log.retention.check.interval.ms=300000

zookeeper.connection.timeout.ms=60000
default.replication.factor=2
delete.topic.enable=true
authorizer.class.name=kafka.security.auth.SimpleAclAuthorizer
allow.everyone.if.no.acl.found=true
security.inter.broker.protocol=SASL_PLAINTEXT
sasl.enabled.mechanisms=PLAIN
sasl.mechanism.inter.broker.protocol=PLAIN
group.initial.rebalance.delay.ms=0
host.name=80.27.75.9
port=9092

#broker最大能接收的单条消息大小(10M)
message.max.bytes=52428800
#broker最大能发送的单条消息大小(11M)，必须大于message.max.bytes，小于服务器的内存
replica.fetch.max.bytes=53477376
#每个Broker上最大的Fetch Session的数量，默认1000
max.incremental.fetch.session.cache.slots=2000

Can someone please suggest on this.

Regards,
gangzi