Hm, I never heard of that. Hopefully someone with more experience will answer you soon. Did you look into the pouch to see how they are doing? Did you try to take them out?
I got them to finally come out before I had to go to bed and then they went back in their pouch but I heard them come out again like a half hour after that. So between midnight and 1am. They usually come out at 9.
I just checked on them. I had them both out of the pouch earlier so I could wash it. When done Loki went right back in it. It's 1am and he still isn't out but lotus is.
It may not be a bad idea for your to have a wellness check done with your vet. If you are noticing a severe change in behavior it could be a sign that he isn't feeling well. I don't typically rush to recommend vet visits, but if you are really concerned you may want to consider it.