You are not alone, my raptor is presently broken but is going to be replaced. My buddy has one though that will be swimming a long then all of a sudden all the action just stops. He's found the same thing, his joints are a little sticky and it seems like while its swimming the joint just decides to stick and it stops all of the action. The worst part is you can't always tell its done it so you ruin a lot of good casts. Its definetely a defect as mine swam great before the joint broke.

Matt