manual support enforcers in specific places. It still makes for easy removal and you don't need a ton, but it helped give better prints.
Also, it almost looks like there was a whole layer problem at about the same time that other tower stopped adhering. You can see a separation in one of the other towers also. Is this in an enclosure? If not, do you have your house temperature go down at night or is it in a room where there is traffic in and out of outside? That looks like a classic large temperature swing on a large print where you don't get good adhesion whne the temp drops quickly.