One thing I’ve always noticed, which I believe is related, can be clearly seen in level 13, the “heart.” If you stand on the highest platforms of the heart, just under the openings in the ceiling, and grab a water bubble from a precise spot, the stream passes through the platform. This is very useful for safely sweeping away enemies or entering the heart. You can do this from both sides, but on the right the correct position seems to be shifted further to the right.