What causes these blue artifacts?

There’s this weird looking blue artifacts, It’s been bugging me for a while but this time it’s too much. Does anyone know what causes these? I tried tweaking the light paths, the materials but it seems to persist… adding a light eliminates these but I don’t want any light and I had similar artworks with little light but this is the only one with these artifacts.

drop your scene here. How are you denoising? I had an issue w/ alphas like this due to the compositor denoise being set up incorrectly

I’m using K-cycle’s ultra denoiser

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