I'm wondering if anyone else uses Clean Bottles for their rides and if so, so you have the following problem?

I use two Clean Bottles when I ride. Usually have water in one and Powerade Zero in the other. I'd say that within the last three weeks or so, both of them have developed leaks at the bottom of the bottle when I tip them to take a drink. It happens on both bottles no matter how tightly I screw on the bottoms. Is this a common problem/complaint, or are mine just wearing out? I've had them both since last August, so it's not like they are all that old.

Thanks in advance for any info provided