As I've already said once, apparently without anyone listening, the GPU-miner is finding only shares, not solutions. I'll use more words:

Finding a share is useless. Competely useless. It always was. It's just that you can't do it without also having some probability of finding a solution (which creates a block). But that's "can't" in the math sense, obviously it's trivial to make code that doesn't actually report the solutions.

So the GPU miner will find shares, making the pool think it is contributing to finding solutions, when it really isn't. Look at the block overview on mine-pool. The percentage is going way up.

This makes you get basically no coins for your useful CPU-mining on the pool, and very little for your useless GPU-mining. Solo-mining still works fine (with CPU), since the difficulty doesn't rise from this. (Unlike the pool payouts you can't fool the difficulty since it's only based on solutions found.)