Hi,
Are you able to reproduce the issue yourself ? (you should see if you get the correct data on PayPal payment page even without paying for the order)
Do you see something specific about the products that were missing from the PayPal payment ?
Also, could you try activating the debug setting of the PayPal express checkout payment method ?
Then, please look at the "payment log file" in the HikaShop configuration after an order with the issue is placed and provide the data relative to the order there.
Finally, another thing you can try is to turn off the "send order details" setting of the payment method and see if you still have the issue (the total paid should match).