Hi,
It's strange - I know 
I think some script could do it but what is strange - not every batch jobs are deleted, and even for example: job X wasn't deleted one day in two days it could be deleted. It happens randomly.
But when I can find if any script is run?
In task scheduler I see batch jobs but - as I wrote in first post - when something delete my batch job I lost this in task scheduler and when I create batch job one more time I can find in hostory that it was deleted by NT AUTHORITY\System and it happens at diffrent time.
Even batch job is deleteed in repository table AL_Sched_Info still this deleted job is active.
Regards