I just upgraded this site from v 1.5.1 to 1.5.4 using the usual process of new folder - check it all - etc.

I seem to have found an odd error though when adding products to the cart from the product listing page

As you can see on this page there are more than 1 product listed :
http://www.mcfigures.com/assassins-c...ns-creed-ser-3

If you add only 1 of those products to your cart you will see at the top in a red error message the following :
PLEASE CORRECT THE FOLLOWING:
... QUANTITY UNITS ERRORS - MCFARLANE ASSASSIN'S CREED SERIES 3 - AH TABAI ADD TO CART:

One error per product with a 0 quantity on the page.

Can someone please help me figure out why this is happening. It only started with this upgrade.

Thank You!
Tina