I currently have an issue placing orders with saved cards using Vault for Braintree. With a bit of debugging, I can see the following error:
Public hash should be defined in /vendor/magento/module-vault/Model/Method/Vault.php:498
I can see when looking at the Request Payload for 'payment-information', public_hash is blank and returns a 400 error. This is on Magento 2.2.2, and just to state, placing orders with new card details works fine, but when using the same card again as a saved card, it fails.
Any help would be greatly appreciated.