Textures gone Wrong in Update 1.12.0.2

When I entered my world when I first saw the update, some of the textures on most blocks ain't there, but when you put a torch on a block, it goes back to normal mostly. Sometimes when you put a torch on a block on those untextured blocks, it turns to a untextured green, or half-textured on a building or something that you built. Even the textures on the doors & trapdoors are half there, and half of the doors & trapdoors is that untextured gray color.