No, it hasn't been fixed. Some folks are just either lucky that they have yet to run into the rather bad decision on how Nokia decided to affix the microUSB port onto the motherboard.

If it were merely a bad batch of phones, I'd wonder why some folks who are quite the Nokia loyalist (past or present) had multiple phones, months or almost a year later in some instances still require replacement?

It's a very bad design choice to just save a few dollars.