Why they appear?
On default image style they are not present.
That looks quite strange. Would you be able to share your model with support, so we can take a look?
This is not a single case, it happens every 2nd or third render/file which include additional image style with blooming and chromatic aberration enabled. Appear on higher resolutions on random occasions. Usually on the "raw"render there are some specs present and from then the post-filters blow a color spot around them.
https://www.mediafire.com/file/cn4g56wzinke0tj/rose.ksp/file
Every speck is anomaly:
more tests on another file:
I had a similar issue with interior mode. Did you try the product mode instead? Just to see if it helps.
Can you inspect the raw render in EXR format (without color grading)? Can you see fireflies / pixels with crazy RGB values (over 1) in this areas? This fireflies with crazy values can lead to strange results in the CA filter.