I have a similar but different bugginess. After my last order was completed 3/4 of the items are still in my cart. I click to remove them and the page refreshes then 10 seconds later they are back in my cart. Been fighting with it for about two weeks now. Maddening. I've put two separate requests in on the site to have my cart contents cleared, but no response.
Grant @Nicotine_River , if you're listening, help a brother out.