I believe it. I have an NCL cruise coming up in April. A few weeks ago, after final payment but before 21 days, I went to add a shore excursion on the website (not through the app). I think I mistyped my cc number and the payment did not go through. But, instead of just not reserving the shore excursion it added the shore excursion to my booking and now said I owed money on the reservation previously paid in full. I immediately clicked to make a payment and this time it went through, and my status updated back to fully paid. I suspect if I had waited a day my entire reservation would have been forfeited instead of just the shore excursion. I was going to add the arcade package for my kids, but now it seems too risky to add anything else before boarding.
