A polarizer doesn’t always reduce reflections—it selectively passes one polarization direction and blocks the perpendicular one.

Here’s why reflections can look stronger:

• Unpolarized light contains many polarization angles, so a polarizer passes only about half of it.
• Reflected light from nonmetallic surfaces like clear coat/paint can be partially polarized.
• If you rotate the filter to match that reflected polarization, much of the reflection passes through while a lot of the surrounding unpolarized light is reduced.
• The reflection may not be brighter in absolute terms, but it becomes brighter relative to everything else, so it looks enhanced and “extra glossy.”

There’s also often polarized skylight in outdoor scenes. Depending on camera angle relative to the sun, the polarizer can deepen some tones and alter what is reflected in the paint, increasing contrast and making the finish look more dramatic.

So the filter is not creating reflections; it’s changing the balance between polarized reflected light and the rest of the scene. Rotate the CPL and you can move between suppressing and emphasizing those reflections.