Sleep Standing

Andrew learned to pull to a standing position only 3 days ago, but he is quite proficient at it. Now, when I hear fussing on the monitor and I go in to check on him, this is what I see:



Only usually he is crying, red in the face, holding on for dear life, clearly confused and frustrated. The only thing I can figure is that he is standing in his sleep and waking up on his feet. Does this point to future years of sleep walking worries for his mother? I hope not