Leaking Costco diapers?

Has anyone else noticed Costco's Kirkland brand diapers leak? My son is a heavy pee'er but we just started having this issue at night. I even sized up and it's still happening. After 6 hours his back is soaked in pee and I have to change his clothes, not fun at 1am. Then he woke up around 6am again because he was soaked, had to change his clothes again! I dont change his diapers overnight unless he pooped. It's so frustrating because we were gifted 2 large boxes of them.