I'm inspecting the cron_schedule table and do see a few jobs with the status "gone":
mysql> select job_code,status,messages,created_at,scheduled_at,executed_at,finished_at from cron_schedule where job_code like "klevu%";
+---------------------------+---------+-------------------------------------------------------------------+---------------------+---------------------+---------------------+---------------------+
| job_code | status | messages | created_at | scheduled_at | executed_at | finished_at |
+---------------------------+---------+-------------------------------------------------------------------+---------------------+---------------------+---------------------+---------------------+
| klevu_search_product_sync | gone | Process "20363" on host "www.example.com" cannot be found anymore | 2016-06-21 07:42:00 | 2016-06-21 08:00:00 | 2016-06-21 08:00:07 | 2016-06-21 08:00:07 |
+---------------------------+---------+-------------------------------------------------------------------+---------------------+---------------------+---------------------+---------------------+
According this post the status "gone" doesn't exist actually. Any ideas what might causing the issue?