A scale of 0 creates a singularity, a mathematical black hole. ⚫️ Consider what happens when scaleX is zero:
some numbers / scaleX
Scale cannot be zero in the setup pose because it could never be any other value in animations. This is because the scale in animations is multiplied by the setup pose scale. Using a very small scale can work, but accuracy can suffer. If that happens it's better to use say 0.001 than 0.0001.
You CAN have zero scale in animations, but you will need to press enter after typing 0. This is so people don't accidentally set scale to zero. It's still not a great idea in animate mode, as it can interfere with constraints or other math. If you find that it does, please let us know and we may (or may not) be able to fix it.
