.sincedb is not updated properly

Hello, I have a problem with update .sincedb database.
Sometimes (not always, but the input files always the same), a new record of last processed file appears in .sincedb only after logstash has restarted by me.

My environment are:
LS: 2.3.1
OS: RHEL 6.6
Config File is:
input {

file {
path => "/mnt/ramdisk0/processing/"
exclude => ".gz"
start_position => 'beginning'
}
}

output {

kafka {
codec => line { format => '%{message}' }
bootstrap_servers => 'cnode1:9092,cnode2:9092,cnode3:9092'

topic_id => 'test_p1_%{+YYYY.MM.dd}'

}

}