Submitted Order is readonly after 2016 Upgrade

Hi All,

We had Upgrade 2016 for the system. And now we get from the Customer the following error - if Order has the Submitted status, the Order record is readonly. 

We got this system for support recently...

Do I correct understand - the access to the Order fields for the record in the Status Submitted is in dependence from some settings in the system?

Thank you advance.