error while saving sales order using order management extension

Summary:

We have created a order management extension which has to default the product group value of the original item to the product group value of coverage item at on save.

we are able to achieve this at submit button but not at save button.

Can you please let us know what was the issue?

Content (required):

Version (include the version you are using, if applicable):

23B

Code Snippet (add any code snippets that support your topic, if applicable):

def CoverVORow = getCovered(HeaderId,FulfillLineId); // we are trying get header id and fulfill line id

if ( CoverVORow != null){ // checking the values are populated or not