Form with changing name

Hello,

 I should do following task:

1. Create order at restaurant.

2. Check email which will be send after finishing order. (order total, tax etc)

I have a problem with checking order total, tax in email. I've got error message: Unable to locate element

I've noticed that form is changed his name:  http://joxi.ru/p27oJJzTRLj427 , http://joxi.ru/DmBx996SOqQxAP

Can you give me some advise ?

And one more question: I can't understand why:

Same test one time is passed, next is failed, then again passed - without any changes.