Throttle filter picking up old instead of new value

Elastic Stack Logstash
2

I've made a test script that generates random data for testing. I've noticed that besides the issue described above the 60 second period is also not always respected and in some instances events get through even though 60 seconds hasn't passed yet.

stdout

         "GPRMC" => "2018-01-06 13:23:45 GPRMC,073126.000,C,3444.4604,C,13521.2644,C,0.15,116.79,261217,,,D64",
    "@timestamp" => 2018-01-06T04:23:45.890Z
}
{
         "GPRMC" => "2018-01-06 13:24:42 GPRMC,073126.000,C,3444.4604,C,13521.2644,C,0.11,116.79,261217,,,D64",
    "@timestamp" => 2018-01-06T04:24:43.021Z