Multi Currency does not work properly

Hi! We are using your MC Plugin and facing some issues recently. A couple of products do not get displayed as the should. There are different prices displayed for different people (all in the same country and currency surrounding). Another related issue can be describe as followed. If people visit our shop (geolocated in country XY) they see the correct price of a product. If they add said product to their cart the prices jumps to a higher position. This is not only very annoying but had as thinking about a plugin change. I’ve asked already for help 48h ago – no response.

I would highly appreciate a response from your side. Find attached several screenshots. Please look at the price. You see the different versions plus the changed price in the cart.

I can offer you access to staging. Let me know if you need it.

Thanks
Bettina