Those cages are made in Taiwan, and Taiwan manufacturing is noted for eventually going lapse in their quality control of stuff that they make.

You say you're doing some racing and training for races, you should consider buying a bottle cage that is known to never fail, break, or toss bottles out of rear saddle holders, unfortunately the one that is world known as being the best is not cheap, and that one is the xLab Gorilla cage, but that cage will last forever. I seriously doubt that you're racing on Shimano Claris components because their cheap, so why use a cheap bottle cage? But like another person said, you do you.