This seems to be a common issue with the 8-PT. I'm glad I'm not the only one having it!
If any of you have read up on Phil Nelson's 8-PT restoration, he mentions issues with magnetism in the cabinet. In his case it pulled the picture at a slight angle down to the side the power transformer was on. Here's that link:
https://antiqueradio.org/rca16.htm
A few years ago, I actually bought two of his 8-PTs off of him, including the set mentioned in that link. I actually swapped cabinets to use the restored chassis in a cabinet with legs (don't worry, nothing was thrown out. If I ever get some time together I'm hoping to restore the other chassis and swap cabinets back), and encountered the exact same problem on mine despite being in a new cabinet! No matter how far the yoke is shifted the opposite direction, it always angles down the exact same way. It has to be something do with the chassis layout.