FMCOMMS5 10MHz External Reference

Hi

I'm trying to connect the FMCOMMS5 to a 10MHz rubidium disciplined sine wave reference. R360 and C348 are depopulated and C301 is populated. The device tree includes xo-disable-use-ext-refclk-enable for both chips and the clock frequency is set to 10000000. Both chips fail calibration on initialization and register 0x5e reflects that neither BBPLL is locked. Is there something that I'm missing to this configuration?

Note: The FMCOMMS5 board is running on a ZCU102.