On my friend's phone, there was a randomly occurring glitch where different items would become glitchy texture-wise when held. Others would be invisible, and other players in the world (on other devices) did not experience the same issue to any extent, other than that when they held the item, my friend saw the same glitch. I don't really have further information, as he was just crafting stairs and then it happened. It was the stairs first, but in the image, it's sandstone. I did search for others reporting this bug, but we're the first. No duplicates... yet.