This happens because cross-polarization depends on the geometry between each light, the subject, and the camera. When you move the camera, tilt it, or let the subject rotate off-axis, the angles to each light change by different amounts. That means the polarization relationship is no longer the same for every light, so one CPL position on the lens can’t perfectly cancel all reflections from all lights at once.

In practice, if the camera position changes, each light’s polarizing filter may need to be adjusted to match the new geometry. The same applies when the subject rotates in a way that changes its position relative to the lights and camera.

So the main fixes are:

• keep camera, subject, and lighting geometry as consistent as possible
• center the subject accurately on the turntable
• minimize camera movement if you want one stable cross-polarized setup
• if you must change viewpoints, expect to re-adjust the polarizers on the lights for each setup

For larger subjects or multiple cameras, maintaining perfect cross-polarization across all viewpoints becomes increasingly difficult, because each viewpoint sees different light/subject angles.