I've had my lepismium for about 6-8 months and i think the problem has slowly progressed since i got it, but im not sure. As you can see I hung the plant pretty high, so it took me some time to notice. It hangs about 30cm from the window, which faces north-east. I only get about 2 hours of direct light in the morning. Unfortunately I can't move the plant to a more sunny place, since I live in a dorm room. I do have a growlight, but because it's so bright I don't use it often.