Blue ring around star in NGC7822

Hi all,

I hope this is the proper place to ask this question.
I have this strange blue ring around the red-ish small star in the center of the image (NGC7822, taken on 2025 02 26 with a Askar 103mm, optolong L-ultimate & Zwo 533mc Pro).
First image is the stack, with photometric color calibration & MAS, second is more processed and annotated. I couldn't find anything about the star or ring on stellarium, Pixinsight annotation or Astrobin, where it isn't there on any image.

I would really appreciate if anyone has info on it or suggestions where to find that information. I find it strange that it would simply be an optical imperfection, as the other stars around it are fine.