I've seen it before. The terminals let loose on the compressor spewing oil all over and all you need is a little voltage or something hot present. It doesn't seem to be product specific though. My guess is that if it's happening in the same complex the voltage is low coming in, compressor strains more than usual and bam... there you go. It's even worse when you have vinyl siding behind the unit, believe me! That's my story and I'm sticking to it.