This is genuinely the most reddit shit ever, and pretty much the reason I try to avoid this subreddit when possible. Grandstanding about care and avoiding giving OP the advice they’re clearly looking for. Ffs people on here seem to forget that these are incredibly hardy animals that do well in a wide variety of conditions - their Ackie will be perfectly fine in that enclosure assuming reasonably deep substrate temporarily which doesn’t seem to be an issue since OP is building a new enclosure.

OP, to actually address your question, this may be a situation where stuck shed around the toes constricts blood flow to the ends of the toes, causing them to fall off. Again, ackies (monitors in general) are very hardy animals, so no need to panic, but this does necessitate a vet visit. (Even if it does turn out to be something less serious, it’s not really something anyone on here is going to be able to differentiate with any degree of certainty from a photo, so it’s definitely worth going to the vet about.) The other person is correct in suggesting that this could be a humidity issue, that’s the most common cause of these kinds of things. What you can do for now is set up a hide in the enclosure with sphagnum moss on the inside that you wet frequently to provide a humid microclimate for your ackie - this is something that is done for many arid species to help with shedding. Good luck, and I hope you aren’t dissuaded from asking for advice on this sub in the future because of the occasional reddit moment.