If she is, and it affects her confidence, then surely it is better that Mum does some plucking, rather than your daughter attempting to do them herself - often young girls think that shaving is a better option than plucking their own eyebrows as plucking can be rather painful. (I once shaved my eyebrows as a very young teenager, and ended up with half of them missing )
I don''t see that it is a childcare issue. If your ex was dressing your daughter in inappropriate clothing for her age and buying make-up etc then that might be a different matter.
I don''t think it''s that normal to pluck an 8 year olds eye brows, however i''d also say your x hasn''t got a chance on hell of plucking her eye brows if the girl doesn''t want them plucked. You''d really need the child to hold still in order to be able to get a hold of the hair with the tweezers!
I''d hazard a guess that as the kid is getting older, it might be that other kids are teasing her and she has asked her mum to do it. In which case, it''s probably best to forget about it. Have you asked your daughter about it directly?
While I recognise this is an exceptionally difficult time for you, Madabout, I think you need to concentrate on what is important in your case rather than on peripheral issues which might increase resentment and hostility and achieve nothing. I know that''s more easily said than done.
This really isnt anything to be concerned about in my opinion. 8 year old girls these days are much more advanced than they used to be - it is possible that your daughter has been on the end of some mean comments by other children and has asked mum to sort it out. I think if you mention this at Court they would think you are being petty and it might give the impression that you are overcontrolling. Young ladies do a lot of preening and most dads wouldnt notice - and like someone else said it is quite painful so your daughter must have been a willing participant! I also wouldnt ask her about it - I would imagine there would be some embarrassment and disapproval if you did.