I’m not sure if this will help you, but as there is no other answers, this will be worth trying.
I assume there could be two reason for this -
1. While creating a job in Control M Desktop, the creator have option to create multiple jobs (even for test purpose). So, if there is a job which is created and uploaded in the system, it can be deleted. So, in your case, this could be one such job which was created for some testing purpose, and then forgot to remove from the system. Got saved in the master schedule and is being forced everyday because of the schedule.
2. Some tweeking with the schedule.
Hope your problem get solved soon.