I had submitted this on github but they were unable to replicate it; and im not sure why because I have been replicating it on vanilla 2.3.... I'm not sure if its a production vs test environment deal or what.
We use the hosted checkout (built-in CC form) and experience the inability to checkout when an ampersand exists in the address fields.
The following gets dropped into the payment.log file:
'RESULT' => '-6'
'RESPMSG' => 'Parameter list format error:',
...and per Paypal documentation this is because there is an '&' in the name.
I'm posting this in hopes im not the only one experiencing this.
It's not uncommon for people to use ampersands in the name field to include both husband and wife. Ex: Andy & Molly in the first name field, and Allen in the last name field.
-Andy
