I am getting a "#10413: Transaction refused because of an invalid argument. See additional error messages for details" with PayPal Express linked to Magento when people checkout having used a discount code on my store. I suspect it might be some sort of rounding error. (I have tried turning off "Transfer Cart Line Items" setting in Magento setup but makes no difference).
This has only recently been an issue and as far as I am aware i have not changed anything in my setup. PayPal express checkout working fine when people are not applying a discount code during checkout.
