Strange artifacts on long-exposure dark scene photos?

[TheFritzinator]

As the title says, I have tried some nighttime photography of the comet NEOWISE in my town. There is terrible light pollution so I knew the photos wouldn't be great, but I would try anyway. To my dismay, large dark-purple blobs appear in all of my photos where light in the scene transitions significantly into near-black. You may need high brightness to see it in the picture (top of screen), but it is definitely there and ruins every photo. I thought it was hardware related but the "blob" changes form from image to image, so it is likely software. In contrast, I used my dad's phone (Galaxy S9) as a direct comparison, and his shows no indication of discoloration. Bottom line is, how do I fix it? I haven't seen anything like this and all my searches turn dead ends.

Photo taken at 10s shutter / 200 ISO Galaxy Note 9

 

[mustang7757]

Hi, welcome !

Did you use night mode option in the camera?