On our mortgage origination system, the acceptance criteria say 'DTI = monthly debt / gross monthly income; auto-decline if above 43%,' and QA has passed everything. In UAT, a loan officer complains that an applicant with $8,000 monthly income and $3,500 monthly debt was declined, but adding the co-borrower's $2,000 monthly income should have made it approvable. Go-live is Friday. What do you do?

房贷系统 story 的验收标准写的是「DTI = 月负债 ÷ 月总收入，超过 43% 自动拒绝」，QA 全部测过了。UAT 时信贷经理投诉：一个申请人月收入 $8,000、月负债 $3,500 被拒了，但加上共同借款人每月 $2,000 的收入应该能批。周五就要上线，你怎么办？