Although I hesitate to call this normal, it's a fact all display technologies have some sort of weaknesses. There's just no perfection.
I get similar line bleeding with my plasma - I have never been worried about it, because of the many weaknesses that came with plasma, line bleeding causes much less picture quality damage than the others.
Buying a TV is a tradeoff between weaknesses. And there are reasons for high-end models to cost more than low-end models.