Octopus Self Destruct

Some people have theorized, is it because of the lack of food? Or is it some kind of self destruct like button or flip that gets switched in female octopuses after they give birth. A handful of scientists describe possible reasoning for this in nature as basically, when an organism doesn't need to use any resources t towards future survival and reproduction. But evolutionary theories aside, there are a lot of questions about why this happens, especially inoctopuses. Caus octopues are really smart, and we are very interested in octopuses. And so why the heck do they do this?