Why is there a halo in Jiao Wai's halo shot by some lenses?

This is because the contrast of defocused binary stars is very blurred, and it will leave filiform traces without complete blur. It is caused by optical design factors and lens manufacturing technology, and generally appears in older lenses and large aperture lenses.

The accompanying phenomena are that Jiao Wai is easily blurred into a light spot and Jiao Wai rotates and deforms.