We have experienced issues with the manual include of the callback class, where the composer class map incorrectly resolved to Magento 2.2 even though we're running 2.3. Magento 2.2 is already EOL for about a year.
The issue manifests itself with failing CSRF validation - in reality it responds with 302 on callbacks and these are then marked in Quickpay as successful.
Example of composer classmap that has resolved wrong:
We have experienced issues with the manual include of the callback class, where the composer class map incorrectly resolved to Magento 2.2 even though we're running 2.3. Magento 2.2 is already EOL for about a year.
The issue manifests itself with failing CSRF validation - in reality it responds with 302 on callbacks and these are then marked in Quickpay as successful.
Example of composer classmap that has resolved wrong: