How did you measure erd and in which direction was the spec wrong?
The rim was stated to be 555mm ERD. For Carbonbeam this value refers to the pure rim.. which is also very clearly visible in the technical drawings.
I measured including nipple head which ads 3mm for Sapim polyax 14mm . This measurement gave 553mm .
So considering that the spoke heads added 3mm to the measurement, the pure rim ERD was 550mm .. 5mm off from the data sheet. That's quite a bit and far away from measurement accuracy.
Whereas Ken confirmed my finding, Carbonbeam still didn't change the wrong number in the data sheet.
My wheel build turned out perfect in spokes length, which adds another proof to the finding. With 5mm to high ERD I would have bought 2mm longer spokes, which would have been a desaster.