This is weird. The cart is adding up numbers incorrectly. Check out the attached image.
I have 1 product @ $385 X 1 qty, plus $32.73 tax, no shipping (that's another issue I'm stuck on, more on that later.) Somehow the total is adding up to $679.57.
Any ideas? Vm 3.0.10. Confirmed this also happens on the Protostar template.
again - try with debug to see whats happening
other things .. check the currency of the product
discounts etc
looks like a heavily modified cart.