I'm on a Nook HD tablet and While using observer blocks I tried to make a automatic pumpkin/melon farm and noticed two distinct things. One the observer does not see an update in the stem of melon nor pumpkins when one or the other spawns in and attaches to the stem making it arch as show in the pictures. Second melons nor pumpkins will grow if a block is on top of the stem even though it grows sideways. I'm unsure how long this has happened before the 0.15.0 Beta update.