I am encountering a bug with tier prices displaying and calculating the wrong percentage saved due to taxes.
I am using Australia GST calculations for this: 10% on all products and tax is included in the catalog price entered and price display. Price display is set to show including Tax in most areas except cart where it shows tax breakdown.
I have also setup two tier prices for this test product if the customer orders over a certain amount.
The prices it shows and calculates in the cart and everywhere else are as expected however the saving amount is incorrect.
It seems to be comparing the bulk discount price without tax to the full price with tax.
If I go into the backend and switch the product to have no tax class the saving sections shows the correct values (10% and 25%).
Magento 2.1.2, Custom theme based on Blank,