I have had two Phalos recently that put up a new leaf that did not open. In both cases the plant put up a basal plantlet. I ended up cutting the non-suture side on one of them, but use a pencil into a small opening at the top to force the other one to open. Unfortunately I could not get it to open all the way to the base of the leaf. It was solid at base, without suture line. The real question: Has anyone else ever had this happen? What were the results? What are possible causes?