When you abort and restart the JobScheduler then (almost all) orders with a repeat interval start only for one time.

If you terminate and restart the JobScheduler in a normal way then it work properly.
But if you abort and restart the JobScheduler then (almost all) orders with a repeat interval start only for one time.
These orders doesn't have a source element in the answer of <show_order ... what="source">. See also JS-956.

For some orders it works furthermore and here you get a source element in the <show_order ... what="source"> answer too.