Sour taste in aged whites

I’ve recently tried some aged whites from Yunnan Sourcing (https://yunnansourcing.com/products/white-tea-cakes-for-aging-sampler-set) and I found the older teas (6-9 years old) to have a sour flavour, particularly in the wet leaf but also in the liquor.

Is this something that other people get too and is it something that is generally appreciated in aged whites? Personally I don’t really like it and I don’t see the appeal of ageing white tea if that is the major change that occurs with ageing.