I experienced this myself. I overwrote then deleted all of my Reddit comments during the blackout using PowerDeleteSuite. A week later they were all back. Some people have speculated that because of the large outage Reddit had during the blackout they may have performed a data restore.
I've since run PowerDeleteSuite again and most of my comments have remained deleted. A couple from several years ago have just popped back into existence in the last few days though.
I've since run PowerDeleteSuite again and most of my comments have remained deleted. A couple from several years ago have just popped back into existence in the last few days though.