The rims in question are double walled rims. That means that they have a large void volume above the tube that can catch water. Looking at the profile
here, it looks to me that there is a design flaw in the rim. The top rim appears to have a rounded profile. I suspect that the spoke nipples don't seal into this channel like they do in other rims. Look at the profile for this
Velocity Dyad rim. It has a similar profile but it has a flatter area for the nipple bed.
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