Probably just a miscommunication. It happened with Godzilla last year as well. Retail was supposed to be one color and ended up a different one so one store is going off of the original info and another is going off of new info or the physical product itself. I'm speculating of course, but it's not a huge leap.
EDIT: I located the source. An email announcing the Transmission web store's opening. It reads,
"AVAILABLE NOW
SHIPPING MARCH 16TH
Zombie Flesh Eaters
Re-mastered in 2014 at Abbey Road Studios.
Cover art by Tom Beauvais
• Green vinyl retail edition
• Gatefold sleeve printed on 425 gsm reverse board
• Includes an exclusive lobby card and booklet featuring sleeve notes by Fabio Frizzi, Ian McCulloch, Stephen Thrower & Tom Beauvais
Exclusive Clear & Grey Ltd edition of 1000 available from
www.Mondotees.com"