This seems to be the behaviour of AWS 'rate' Cloudwatch events. Eg. rate(1 hour)...

mcintyre1994 on Aug 28, 2019 | parent | context | favorite | on: Lessons we learned when debugging a scaling proble...

This seems to be the behaviour of AWS 'rate' Cloudwatch events. Eg. rate(1 hour) or rate(10 minutes) don't necessarily run on the hour. Not sure if they're relative to when you set them up or random though.