"Update, I took the '20 apart and yep, it was back bowed. I went counter 3/8ths of a turn and set the ruler on it, it was straight. I let it sit for 2 days and rechecked it, it has a teeny bit of relief now. I came back 1/8 clockwise and will let it sit a day or 2 to see what it does."
Are you doing this with the neck attached to the body and then leaving it under tension with the strings on?