i have created a field named total discount and computed the below code for it using studio 
for record in self:
record['x_studio_integer_field_at_1h4b0pdc1'] = record['amount_total'] - record['amount_untaxed']
this code used to generate a number that was the subtraction of amount undiscounted and amount untaxed but suddenly after 5 days this code does not work and wont effect the output of my custom field i have tested it on multiple databases but it doesn't work . has something changed in odoo causing this issue???