Glass and Glowstone textures are purple and black when summoned with command blocks

While watching a recent ethoslab video Boats + Slime Blocks = Gliders etho showed two commands that would let you run anywhere and tnt would appear beneath your feet. I tried this out and changed it to glass for the fun of it and the texture in the screenshot attached appeared. I replaced the command block text from glass to glowstone and the same thing happened. Same texture. Solid blocks seem to work fine but just those two I had trouble with. I do not have any experience with command blocks and am more of a copy and paster with cool commands. Thanks, have a wonderful day!