Promo codes "Restrict to categories" Discounts entire order, regardless of category.

[doug86i]

Describe the bug
When restricting a promo code to a category, I would expect only that category to be discounted. However when calculating the total at checkout the entire order is discounted.

As a side effect, Promo codes restricted to categories can also be used more times than the "Max" set as long as purchases are made from categories outside those set as "Restrict to categories".

To Reproduce
Steps to reproduce the behavior:

Goto: https://portal.offbeattickets.com/event/pcbd

Use promo code TESTTEST

Add a non-discounted ticket to your basket

See price calculation on checkout page.

Expected behavior
No discount should be given for tickets outside the allowed category.