Are you using a TDI flywheel set up and TDI input shaft?
I've got a 1Z tdi flywheel that's been machined a bit to make it fit, a VR6 pressure plate and the 2.1WBX friction plate. Standard diesel input shaft.
I've still got the old friction plate, i'll dig it out and compare it to the current one. Seems the problem is that the center section is larger on the version i have currently which is fouling on the guide tube. I'm not positive on this as i've not compared mine yet, but Aidan reports that he's compared a couple of identical LUK friction plates and the center section is larger on one of them meaning it can foul on the end of the guide tube.
Like you say, may well not be LUK particularly, but seems there's a slight design change that means they're not fitting so well in a hybrid tdi clutch set up. They're probably fine in the intended application in a WBX, but certainly seem to be causing some issues with this kind of setup.