cobblestone wall texture glitch

i was recently on my survival world and was makeing a staircase to go up to the second floor and wanted to use cobblestone walls to make it where i dont fall off.

but when i made the walls and held it in my hand it had part of the cobblestone wall texture and some of the bookshelf texture.

i tried to go into creative to hold it place it and such but to no previel.
i also tried again in the same world i saw it happen but again, nothing.

it happened one time but one time should be enought to help not make it do it again in the next update. 🙂