Hello,
we are currently experiencing the same issue at the Checkout page within our shop.
We are using the free-version 1.4.3 butt the issue still remains.
I would fix the plugin .php myself, but I could not find the line which causes the ID exposure.
The shop-system can be found here If you want to check the issue:
https://b2c.bt-innovation.de/checkout/
It’s currently set-up to display an upsell offer if you have one of the sealant products in the shopping cart.
