Can't insert record. "The record cannot be inserted because these data have been already sent"

I have a simple add form which takes global variables as input from linked grid application.
The form has only this code
Events onLoad :
{operator} = [operator];
{customer} = [customer];
{site} = [site];
{subscription} = [sub];
{subscriptionId} = [subId];

It is simple form as it is.

And I use edit-mode button on the main menu application. The user should have to checked on edit mode button to change the database into read-write mode. If user forget to checked on edit mode and click ‘insert’ button it shows database error as expected 'command denied to user… '. This works fine!

The problem occurs when user clicked ‘insert’ button again after checked on edit mode button. It shows error as The record can not be inserted because these data have been already sent. But the data is not stored in the database. What is the problem? I have other forms which works perfect with our ‘edit mode’ and with the same steps. I can not figure out why this error occurred only on specific form.

Some time ago. was reported this error, maybe it can help you.

Thank you @alvagar! It seems ScriptCase bugs.