I'm going to try to make this as detailed as I can, I have seen some other people who have just full on posted stuff and like "Fix this I dunno what happened!" So, occasionally (not all the time) fences, and blocks textures will be glitched when held in hand. This includes all fence types, and all full blocks such as tnt, droppers, dispensers, and maybe grass blocks. I have an iPod Touch 5th gen, iOS 9.2.1, and my Minecraft PE version is 0.14.0.

Thanks! - Clay C.