Keep it simple - and watch the obvious!
In any circuit, what happens if you have a short to ground? Current keeps flowing, that's what.
If that short occurs after the load, the load keeps running. If the stop buttons are after the short- AND after the load- the load cannot be disconnected.
So, it's not a matter of the 'stop' coming first, so much as the load coming last.
Placing 'start' contacts before the stop contacts can also create a situation where the 'stop' button doesn't work. The whole purpose of using relay contacts is to 'get around' open contacts, after all.
