Hi, we were having a issue like this, in my case when saving SO also removed all information or change to the default address from customer. The scenario was when using a custom address, the user mark the Override check, then put in custom information or instructions, then when saving the Sales Order the information just disappears. I raised a case with Netsuite support, and told me that the system is expecting mandatory fields like Country,ZIp Code etc. so at saving could figure out and remove information.