Thanks for the reply.
Unfortunately it appears the the foot of each mount is still secured well, but there is play in between the foot and the mount that causes the movement. I think I will call Yakima today and get their take too.
BTW, has anyone ever used a regular wheel skewer in place of the locking ones that come with the bike racks? One of mine is missing - either fell off some how or was stolen, and I would love to just use a regular wheel skewer laying around. The diameter of regular skewers is quite a bit less though.