This happened within a few hundred light years. Because we're seeing the left-over crumbs in their final orbits, it also must have happened recently.
This could be either the natural death-throes of planets circling a spent white dwarf, it could be the decompiled planets of a post-singularity civilization, or it could be a civilization-exterminating alien force on its way to Earth right now!!!!!1!!!1111
It's probably the first one, but singulatarians should be looking for evidence like this in surrounding star systems. In particular, since we should expect this phase of an old system's evolution shouldn't last long, we shouldn't see it very often. If we do, something else is going on. So do we see more of these kinds of systems than we would otherwise expect to?