Can't buy a bundle

[Soulessgingr]

I am trying to buy the FANTASY GROUNDS D&D COMPLETIONIST BUNDLE but i got this message:
Note: One or more of the items below have changed in price since you added it to your cart.
And I just can't buy it.
Any help PLEASE!!

[Gonks]

My initial guess (and I'm only wondering out loud here):

Maybe something inside the bundle was on sale individually as well (when you added the bundle to your cart) and has since gone off sale in that time.

What happens if you remove the bundle from the cart and then add it back in?