Down the Rabbit Hole incorrect XP when removing 2x copies of upgraded card

[Neofalcontoo]

I have Down the Rabbit Hole, and 2x Prepared for the Worst (0)

I remove 1x Prepared for the Worst (0) to purchase an Enchanted Blade (3). This is correctly reflected as costing 4 (3+1) xp.

However, I then also upgrade my other Prepared for the Worst (0) into a Prepared for the Worst (2). This should cost 1xp, bringing me up to a total of 5xp spent. However, when I do this, it's still showing a total of 4xp spent:

The issue seems to occur when you purchase a new card to replace a level 0 copy of a card that you are also upgrading another copy of. Because if I choose to replace a different level 0 card for my Enchanted Blade, it correctly shows a total cost of 5xp: