I'd be explicitly entering 4-digit years into the dates -- 7/30/2017. It might think you mean 7/30/0017.
I found similar issue on my FMS15.
There is a schedule "run once" I tested last year (2016/12/29)
This have grayed date "02/11/30" for end date, when setting it appear as 0002, not 2002...
I can't recall when I made this schedule, and whether I set end date once. This server first used with FMS14.
Newly created schedule have same date as start, no problem there.
Excellent thought. Of course, I did try that first, too.