Even I'm facing similar problem.
I'm currently using an AD9548 with a 10MHz OCXO as an system clock input. The problem I'm having is that the system clock will not remain stable (checking via system clock stability signal on a M pin) with the duty cycle of the OCXO I'm using (45/55).
R0x0101 = 0x64
R0x0102 = 0x45
Kindly help!!!!! Thanks for your help