ADRV9009 ZCU102 DAC/ADC mismatch

Hi there,

I'm using the adi module in python to transmit/collect data.  I created a square wave at 1 Mhz (LO = 1GHz) to be sent to my DAC and noticed that the waveform appearing on the ADC had these step features.  I noticed that if I changed the variable trx_lo, I could tune the ADC code where these step features occur.  

I was hoping that at integer multiples of 122.88 MHz I might see these step features disappear, but that is not the case.  I don't understand where these step features come fro from and why the LO frequency would be a relevant parameter at all.  Can someone explain?  Thanks!