Thanks! I see that when I put the text position point on 960,540 the text lines up with the white solid masked behind it. Looks like one should create captions and citations on normal 1920 x 1080 text layers. Then layer, mask, new mask for appropriate cutouts (made rectangular), before being copied to white solid.
Nest the white-backed text and only then change text position to where it needs to be.
Thanks to your suggestion we’re back on the right track! Happy holidays!