After recently upgrading to 2.3.5p2 EE, we encountered an error when a customer placed two magento orders in close time proximity to each other.
The first order worked fine, and Magneto recorded both a correlation id and an transaction id, but for the second order Magento completed the order, but there was only a correlation id.
There was an error logged in system.log:
report.CRITICAL: PayPal NVP gateway errors: A successful transaction has already been completed for this token (#10415: Transaction refused because of an invalid argument. See additional error messages for details). Correlation ID: 1251d12bc66e7. Version: 72.0.  
There have been other reports of this happening, so I was wondering if there was a definitive fix.
Why would Magento create an order if paypal returned an error?