Same issue in my app. iOS 15.4, 15.4.1,15.5 will not return valid products since April. In the early days, some will success , but in last two weeks, none will return valid products.

Finally apple has helped to solve the issue on our App. It is due to having 2 duplicate bundle IDs (aaa.bbb.ccc, aaa.bbb.Ccc) in Apple's system. And when we tries to fetch Product information for aaa.bbb.ccc, it will always return those from aaa.bbb.Ccc instead. Apple has helped remove the aaa.bbb.Ccc, and it is working properly now. Hope this information will helps to those who have same issue.

Contact Apple, they will help remove it from database manually.

fixed by set first.contentType = .newPassword and second.contentType = .password