[dmforcier]

As Worth indicated, depending on the circuit it is legitimate to use any color wire. The black=hot and white=neutral arrangement is conventional, but not absolute. (Green must be ground, I think.)

However, best practice is that the installer "label" both ends of non-conventional color use. The 'best' way is to wrap some tape of the "correct" color around the insulation below the join. With white wires, the installer will often color the insulation with a black marker.

NWG, you can see that the installer used a white wire for hot. You could color it with a black marker as a reminder (especially if you disassemble to replace the box). Now you should be interested to find the other end and mark it, as its use as hot may not be obvious at the other end.