Wrong price and order subtotal calculation when using a promotion + a promotion with coupons

If a bug, provide steps to reproduce it

1. Clean install, only make sure variation price is calculated, not default
2. Add product 1 (price $30)
3. Create first promotion "50% Off Prod 1" (Include the discount in the displayed unit price)
4. Create second promotion "-10 from order subtotal" and a coupon.
5. add product to cart, apply coupon, proceed to checkout

Expected results

Actual results

If there's no coupon applied, the product price, subtotal and total are correctly calculated

I'm not sure if this bug is new but right now there's no way to have a promotion for a product + a coupon for the order subtotal.

Thanks.