We’ve received a large amount of feedback about Legendaries becoming unreachable. This is actually a topic we’ve been tracking for quite some time. To ease your minds I am here to say that it’s something we’ve been watching and we’ve been listening to your feedback. You can expect to begin to see changes addressing the issue starting with our next build.
For those trying to craft and convert items for a legendary, I'm not sure if saving your mats until said patch is a good idea or not but just a heads up, they are going to change something about Legendaries!