I understand this might be different to provide a repro.
Do you have any code change on your side?
Maybe you could start with creating a side project with your code, based and check if that issue repro there.
Looking at the picture, I would sayd the final hair composition (going from the hair strands lit buffer into the main scene color) is no happening. This is why you have this strange color + partial hair. Maybe something related with filtering out transluency rendering in your scene capture? Or a postprocess material?