X-ray diffraction can reflect average structure: in disproportionation, atoms may be displaced slightly to either side even though the average pattern places them in the middle.

“it's just average it's just average behavior but like for example disproportionation is a very complicated thing right where it's possible that you're the perfect crystal and on average it looks like it's perfect XRD but in reality there is some other pattern going on where like atoms slightly shift to the right or left but on average they're in the middle yeah it's a difficult life yeah”