It's tough to pinpoint when it started, I rarely print out of photoshop. It popped up a week or so ago, but I was on a deadline and had to just work around it. It had probably been a couple of months since I'd printed from photoshop before that.
Custom paper sizes don't seem to help. In fact, whatever size I change it to, the oversized print area changes in proportion! I've attached screenshots that show changing the size to a #10 envelope (4.12 x 9.5 in) - and the print area changes to 23.736 x 10.292.


I've never seen anything like this. Does signing into another user account and using Photoshop there give the same results?
With your CC account, you may also download and use an earlier version of Photoshop, CC 2018 19.1.7 as an example, and see if the same problem is there. (Also a good idea when CC 2019 glitches hold you up.)