Hi,

In the create() method, you should not directly modify the values dictionary that is passed as an argument because it can interfere with the creation process and lead to unexpected behavior.
You can use the write() function to update the newly formed record after it has been created in order to correctly handle additional computations throughout the create process without directly altering the values dictionary. Here is how to go about it:
def create(self, values):
        my_model_line = super(MyModel, self).create(values)

        # Additional computation goes here
        # Example: Calculate the value based on quantity and price
        value = values.get('quantity', 0.0) * values.get('price', 0.0)
       
        # Update the value field of the newly created record
        my_model_line.write({'value': value})

        return my_model_line
This method uses the write() method to update the newly formed record's 'value' field rather than directly altering the values dictionary during the initial construction process. By doing this, you can make sure that the Many2one field and other fields behave correctly while new records are being created.

Hope it helps