Oops it appears the IF node doesn’t like textureobjects, and yes the flipbook node needs them. I was hoping that would work. Don’t worry, you can make it work, but in this case the easiest way is to probably do the same thing, but use 3 flipbook nodes. Then you put the Flipbook node outputs themselves into the IF statement inputs just like you had the textures input. that should work.
Just make sure each flipbook has the right textureobject.