Sorry, can’t find your other post about that wire break.
IMO the other two phase wires have also been exposed to whatever caused that metal fatigue in the broken wire.
You can see the bends in the other two phase wires at approximately the same location as the broken wire. I recommend stripping the other two wires to check for damage. It could help determine the cause. Whatever it was it seems to been done to all three wires and was quite strong. It takes a heck of a lot of bending to snap that wire.