I have a Whippet and have had the same problem with the deore chainset granny ring rivet tabs grinding the bb shell. The problem seems to be the very small clearance(sub 2mm)combined with gritty mud, the granny ring itself isnt rubbing.
I had a look at a Scott Scale 30 yesterday in my lbs which has the same fitting and looked to have a similar clearance. I was wondering if this is an issue that has been seen on any other press fitted bb bikes running triple rings?
I am waiting for On One to send out an XT chainset which should hopefully, as Firestarter says, have a bit more clearance.