After loading into Minecraft, if a world is loaded while RTX is off, it will fail to load textures correctly and all blocks have the default shiny texture, then if you reload the world with RTX enabled, it loads the textures.

After trying to reliably recreate the issue, it seems that if RTX is enabled when loading the game, no issues occur, but when loading the game with RTX disabled, then enabling it in a world, the textures fail to load, upon reloading the world with RTX initially enabled, it works.

In the video, RTX is initially disabled, a world is loaded, then using the colon/semicolon key, RTX is enabled, textures fail to load, the world is reloaded, and the textures load.