A hole in the Oak Sapling thrown entity texture, in-hand texture, but not on ground texture. Go into 1.9 and then open a world and throw a oak sapling on the ground, wait for it to spin a few times then, part of the side turns PINK!
You can also briefly see it when you place it that there is pink on the sapling your holding. If you pause the game at just the right moment, you will clearly see that the side of the sapling is pink too, but when you look at it on the ground, it's totally normal... not to sure whats happening THERE! Besides that, love the 1.10 snapshot! Nice job with the game so far! BTW, I chose 1.9.2 because 1.9 didn't appear. Another bug! Make sure to fix that too!
Does this happen in the latest versions: 1.9.4 and 16w20?