I think your kitties are probably unsettled still from the move and marking the space. I would be relaxed about it, but I would also take them to the vet to make sure everything is all right physically. If the problem contines or gets worse, then you will need to look for other causes. For now, I would take the easy way out byjust loving the kitties, helping them feel more secure in this strange place. The missing the box business is usually caused because the box is too small.
Most litter boxes are tiny, and kitties have to crunch up to get things into the sand.
I used to miss my box frequently until my humans got me a bigger box. Now I have space inside to assume a nomal position and I never miss the box. Another cause of missing the box is a dirty box. You should pick it out every day. This is especially important when more than one cat is using the box.