Make sure some part of the stack is not getting caught on a ridge on the freehub body and not seating fully. Aluminum freehub bodies can gouge easily especially with the partial spline design used by the 10 speed loose cogs. This could be easily verified by seeing if the last 3 cogs on the carrier are loose when all of the other cogs are installed. Have you tried individually installing cogs to make sure they all slide on smoothly?