There seems to be a bug when using a territory that has tax and then adjusting the quantity.
With EU selected VAT is included in the base price and the new discounted price as expected but when I adjust the quantity the page refreshes, ‘including tax’ disappears and the original price displays without tax included but the discounted price still displays with tax included.
(This is on each individual item’s prices the totals still remain correct)
Refreshing the page then restores the correct tax included price.
I’m using the DAWN theme and adjusted the code following this thread to display the compare price on the cart page.
https://community.shopify.com/c/shopify-design/cart-checkout-compare-price/m-p/1966619