A small quantity of rims from the first production batch, (Q1A shipment of Feb/March 2018) have a partial Vibrocore foam blockage in nipple holes. This could prevent nipples from seating properly in the spoke bed during wheel building. Model: Spike 350 Vibrocore Rims, 27.5” and 29”Identification of blockage: As shown in photos below, when viewing through nipple access holes, you should clearly see both openings.  (Picture on the left).  In the example of the right, the nipple hole is slightly obscured and may need some cleaning before inserting nipples.
Perfectly cleared nipple hole
Partially blocked nipple hole
Correcting the Issue:  Using a 7.5mm diameter drill bit, lightly insert and gently turn to clear the excess foam.
PLEASE NOTE: This minor foam excess occurred on a limited number of the first production rims. The issue is fully resolved and limited to this one batch. It is not a standard or recurring issue.