nrf52832 HFCLK not indicating start

Question

I've got a set of boards that are behaving very strangely. I attempt to turn on the HFCLK but the HFCLKSTARTED event never comes nor does the HFCLKSTAT register indicate that it has turned on. 
 However, my scope shows quite clearly an 850mV peak-to-peak signal on XC1 with the upper peak at almost exactly 1V. This signal looks identical to that on XC1 on my PCA10040 development board. (edit, Yes, the signal is 32MHz to the resolution of my scope (an Agilent MSO7104A). Sorry I forgot to put that in originally). 
 What is the internal criterion that the nrf52 uses to measure that the external clock has started? 
 Thanks. 
 (I'm using an NX2520SA-32.000000MHZ crystal. The odd part is that I have other boards that work perfectly with this crystal using the exact same parts and schematic, so I'm really baffled.)

Andrew Lentvorski · Accepted Answer

For future reference in case someone else bumps into this, the issue was a manufacturing fault that put a 10K resistor from DEC4 (pin 46) to GND rather than the expected 1.0uF capacitor.