PLL on ArriaGX GXB won't lock

[Altera_Forum]

I am having trouble getting the PLL of an ArriaGX GXB to lock. After bringing the GXB out of powerdown the tx_clockout starts to toggle as expected. However, after a short time the toggling stops and the PLL never locks. I have verified this both by signal tap and using an external oscilloscope by running the tx_clockout to a test point on my board. The general purpose PLLs on the board will work as expected and lock with no issue. 

 My test project is simply an instantiation of the GXB and reset/control logic to follow the reset procedure in the ArriaGX manual. I can compile the same project for an ArriaGX evaulation board and the pll locks as expected.  I am using a 62.5MHz crystal oscillator (same one used on the ArriaGX evaluation board). The clock is very clean/stable at the REFCLK input. Given that it is the same part as the eval board I know it meets the specifications required for the refclk. The transceiver power supplies are powered by linear regulators (same parts as the evaluation board). The supplies are the correct voltage and do not appear to be noisy. I have tried changing the PLL bandwidth within the GXB megafunction wizard but it does not help.  Does anybody know of something that could be causing this behavior? I could understand if the pll didn't lock for some reason, but I don't understand why the clock stops toggling altogether. My thought is that since it works on the eval board it is not firmware related. I have to think it is a hardware/noise/grounding issue of some sort, but I have not been able to isolate the problem. I'm wondering if others have had a similar issue.