The problem with finding a physics bug is that it's liable to be amplifiable. Break conservation laws just a little bit and suddenly you have potential for exponential runaway leading to an unplanned reality excursion, and say goodbye to your light-cone.
And, if a very bad reality excursion happens, you scrap that branch and restore the last checkpoint. Nobody inside the simulation will ever remember it. You only bother fixing it if halt/scrap/restore becomes a burden.
It probably happens more often than we imagine ;-)