If misting is normal, why have they flagged it?
For the same reason they flag tyre tread and brake pad wear- well before the item is due for replacement.
I was told there was some misting on one of mine at last service- and was also told that was usual.
I wouldn’t worry about it.
You could argue that almost every component on a used car is “ on its way out “ so should be replaced now.
I doubt you’ll get very far with VW if their official line is that it’s usual, and has to be leaking before they replace.