Im assuming this is a setting box that has been missed somewhere,
When our customers purchase a gift a card from outside of the UK they are charged the ex VAT price.
Ie someone in the USA buys a gift card with a value of £120 but are only charged £100the ex vat price
Which gets a bit more complicated when they have gifted the card to someone in the UK as we the business will have to cover the £20 (or Vat difference)
While UK customers buy a card at £120 and get to spend £120
Hope this makes sense.