About change operation sequence

Hello,

When i want to change operation sequence if i dublicate the number and then make it true, it doesn' t save the changes. If i don' t dublicate and give a unique sequence number it can save.

It' s hard to explain to user. Do you see anything like that? Is it usual situation or just happend to me?

Example:

First routing

Changing the first one and having the error as normal

Changing the second one and error dissapear

And at this point when i try to save, jde acts like saved but doesn' t.