Hallelujah ??
I have found he following set of WC fields and added them to both Custom Field Blacklist & Protect List. I really do not have time to test, but I seems to have worked.
_regular_price
_sale_price
_price
_min_variation_price
_min_variation_regular_price
_min_variation_sale_price
_sale_price_dates_from
_sale_price_dates_to
_stock
_stock_status
_tax_class
_tax_status
Hope this helps
