Difference between cart value and shipping bar

Hi All,

when i use a voucher (from YITH Woocommerce Frequently Bought Together Plugin) (see Screenshot in blue marked) the total value between the cart and the plugin message is different. It is jost 0.80€ ?! See also Screenhshot attached. I dont know why this is happend and how i can solve this? When i delete the voucher everything is okay….

If you needed i can create an Access to my staging side….Please let me know. Thank You!