Recently I have started learning to draw. I watched some proko tutorials to learn the basic idea (that I'm generally supposed to think in 3D, what are bodies made of etc), consulted some books, watched some paintings from the past to see what they did etc. At the moment I still need a lot of practice (of everything, basically) so I still draw like an elementary schooler, but in general I've been having fun and I liked where I was going.
Recently, however, I recall that way in the past I heard some statements by people who uploaded images on the Internet who were greatly dissatisfied in their ability to draw, and where they are as an artist, and blamed that on learning to draw some way which permanently (?) gimped their ability create the art they want. Usually they referred to manga-style, but I've also heard of someone who tried to copy pictures by hand (in an effort to be a hyperrealist artist), realised that despite being able to copy extremely well he does it a "wrong" way he's dissatisfied with (I think he couldn't do anything beyond copying), and had to relearn everything from the start.
Are those real dangers I'm about to get myself into? I don't really recall any skilled and accomplished artist to talk about it, is it because they never encountered any such problem, or is it a made up issue? Is there a way to avoid such a great flaw?