I wonder about it being lack of water (a bit like the crinkling of the leaves).
What Bryan says makes sense, as I get leaf crinkling because of underwatering but I don't get this problem and I DO poor water all over the leaves when watering all my oncidium alliance (especially over the summer when they are in the greenhouse).
I was told by someone working in one of the orchid nursarys that doing that was a good way to reduce the leaf crinkling if I'm scared of rotting the roots, but it could also be helping with the spiking