Odds are yes. I had one for a few years and every couple months he would Block himself into his tube, and not come out, sometimes for 1-2 weeks at a time. I just let him be, if he was in there for a week or more I would put a piece of second soaked Fish in the end of a toothpick and gently knock at his door, he would generally move a rock out of the way grab the food then close the door behind him. Just because sure to give him space and tim, you don't want to stress him out during a molt, and you don't really even need to feed him as he will eat his molt after he is done.
Mantis Shrimp constantly excavate/customize their burrows/dens. Whilst it is certainly true that when they molt they do block the entry/exit points to their burrows/dens to prevent predators from accessing their completely vulnerable soft forms, however another reason might be that it has excavated another entry/exit point that it prefer to use than the previous one it blocked up.
But I'd be leaning more towards the molting, it's very important that they be allowed to block up their burrows/dens specially in a mixed animal tank, potential uneaten and live food can turn from intended food to predator, I knew a person who lost a Giant Spearer about 30cm long to a bunch of small hermit crabs that ate the spearers 'head' because the mantis was completely incapable of defending itself even from normally harmless to them creatures.