I reckon its a case of the rear of the spokes.
Like with mk3 and mk4 RX11's.
With standard alloys on my 288mm brakes there is next to no clearance, and i mean no more than 1-2mm.
So with these allloys having rather chunky spokes i reckon thats your problem.
Stick some 5mm spacers on, that dont need to be hubcentric or longer bolts, and you should be ok.