If they work OK, I wouldn't worry about it. If they don't, toss them and try another brand. It sounds like they are a bit small, but unless they drop out or the catch does not engage, there should be no problem.
If the rattle really bothers you, try this. (There is a risk of damage to the magazine, so be warned. ) Using a vise with padded jaws, insert the magazine between the jaws flat ways, that is with the side of the magazine up. The bottom lip will be outside the jaws. Then close the vise, squeezing the mag until it bulges slightly. If the mag is not damaged, that should fix the rattle and let the mag release engage better to boot.
Jim