Hey guys, I contacted Koolance last night after posting here. Their reply:

"We have only seen this issue two other times, it appears to have been a change made in the cards design as many of these blocks have been sold without an issue. Currently we are considering solutions for the affected customers, this could entail replacing the mid acrylic with a thicker piece, or supplying a different PCI bracket and support screws for either end."

Hope this helps, you may want to contact them directly.