I found these too after installing your plugin. I have literally many dozen of these:
hook – 1441044271
schedule – single
next execution – on next page refresh
The next hooks go:
1441044273
1441044332
1441044342
…
–I don’t have any caching plugins installed.
–I have tried clearing the cron options in the mysql table wp_options, to make wordpress rebuild the cron schedules
These are the cron schedules that your plugin lists in the upper right:
Cron Schedules
wpo_daily – Once Daily
wpo_weekly – Once Weekly
wpo_otherweekly – Once Every Other Week
wpo_monthly – Once Every Month
hourly – Once Hourly
twicedaily – Twice Daily
daily – Once Daily
wpo is WP Optimizer plugin. I don’t think this is what’s causing the cron jobs with unknown hook.
The only other plugins I think might could be causing are AdRotate Pro, Related Posts by Taxonomy, Revision Control.
I would really like to solve this problem, as I suspect the many cron jobs with the 8-digit hooks are clogging up wp-cron and I have scheduled posts that are missing schedule. One time I tried deleting all of the strange cron jobs using your plugin, and scheduled posts worked again.
Any insight you could provide would be much appreciated.