Could just be a natural soil mite that’s churning the detritus for you into another form of nutrients ready for micro herd to convert.
soil biology is vast and required for making soil recipes etc.
Have you checked out the following to see if anything matches?
Oribitad mites
Mould mites
Hypoaspis miles
Also try searching “worm bin mites” and see if any match.
have a great Christmas.