Weird lines appear after doing Filter-Other-Minimum

Photoshop 23.3.2; Windows 10

Hi,

I'm trying to do star reduction on my milky way raw file (Nikon D850, Rokinon 14mm).

Following several youtube videos as a guidance. The stars are reduced, but some weird line pattern appear spreading out from the image center. Please see screenshot. The exported PNG also shows the weird lines.

All I did was:

Select - Color range. Highlights, Fuzziness = 60, range = 100

Select - Modify - Expand. Expand by =3

Select - Modify - Feather. Feather radius = 1.5

Filter - Other - Minimum. Radius = 0.8. Preserve Roundness

I have played with different values, with the same results.

No other sliders had been moved prior to the above.

Thank you,

Azman