Interesting, it's simply a few thousand nested divs with a huge blur on them. Is it something specific about blur? Or could you do the same thing with box-shadows, etc, if there are enough of them?
-webkit-backdrop-filter forces layerization (i.e. it promotes whatever box it's in to a Core Animation layer), while box shadows don't. This resource exhaustion bug is specific to CA layers, so you wouldn't see this with box shadows.