Hey Thomas,
This is due to the fact that free tier services run on a machine type that can be restarted on short notice. This doesn’t impact most free services because they usually spin down and get scheduled on newer machines. It appears that your free service is almost always up, so it rarely gets rescheduled and will get restarted more regularly as a result of the machine restarts more regularly.
This obviously isn’t a great user experience. We’re looking into options to address this.