Sometimes babies go through times they start retaining there urine as long as they are still peeing they cut of is usually no wet diaper in 6-8 hours give it a bit and see if it returns to nothing because he’s still having wet diapers just not as much
I had that happen with my baby once when she slept the entire night as well. I waited a little bit to call pediatrician and noticed she was back to the normal constant peeing haha. So I didn’t call but it might be because your LO didn’t drink as much as they usually do. Call let pediatrician know! They’ll probably tell you to keep an eye out and if nothing changes they’ll have you go in