Little Big Disk TB output distorting on iMac?

Hi Folks,

I have a new 2011 11' MBA Ultimate.

When connected to a 2010 27' iMac via display port the screen is great, with a very stable picture.

When I plug a Little Big Disk into the MBA via a TB cable and then use a display port cable to connect from the LBDisk to the iMac I see small distortions every 5 mins or so in the bottom 25% of the iMac screen.

Take out the LBD and the pic on the iMac is perfect, no distortion.

My evidence points to the display port output of the LBDisk.

I contacted Lacie and explained the evidence I had.

They wrote back and asked if my cables were OK?, even though I indicated that with the LBDisk out of the daisy chain, the pic was perfect.

Any one else experienced problems with the display port output of the LBDisk to a Mini display port (input of