My little guy is in the four hour E.A.S.Y routine as he's 5 months and a few weeks. He was doing so well on it for weeks, sleeping fully for both 2 hour naps and his catnap. Now suddenly he goes down only to wake up in about 30-45 minutes. Sometimes it's impossible to get him back down, other times he will go back down, but it means me patting his back in his crib for 20 minutes. Night time seems to be okay, although sometimes he'll wake a few times before he's out for the night. Is this common that they do so well on their routine and then start to fall out of it again? Curious as to why?