Science is not as black and white as it's made out to be. In this particular case, the observation seems to have been made with scientific rigor, so this part is definitely scientific. As for the parts of the causal chain that are not fully understood, these will be subject to further inquiry. It would be fair to call those parts "a mystery", but that doesn't imply them having any "mystical" properties. "Mystical" to me would mean "fundamentally outside the realm of scientific inquiry", not just "we have not gotten around to it yet".