[account_mtd_vat] response_from_hmrc field ends up blank in 'redirect_uri is invalid' scenario

[Nick-OpusVL]

(Pdb) l
 52  	        if response.ok:
 53  	            return {'url': url, 'type': 'ir.actions.act_url', 'target': 'self', 'res_id': record.id}
 54  	        else:
 55  	            response_token = json.loads(response.text)
 56  	            import pdb ; pdb.set_trace()
 57  ->	            error_message = self.env['mtd.display_message'].construct_error_message_to_display(
 58  	                url=url,
 59  	                code=response.status_code,
 60  	                response_token=response_token
 61  	            )
 62  	            record.response_from_hmrc = error_message
(Pdb) response.text
u'{"error":"invalid_request","error_description":"redirect_uri is invalid"}'

Found in 8.0, possibly in all