Do you have the hardware design of the customer or a layout design of the board as well? Or is the customer used the evaluation board? Radiation can be a possible cause but not proper layout of the board can cause unwanted signal as well. Is the 124Mhz and 63Mhz a component of a possible source like oscillator or a switching frequency of a power supply. The frequency of some component can easily couple if the layout are not grounded properly. One way to isolate, if possible is to use external sources first, like external oscillator or external supplies.
Your multiple posts for this issue violate the code of conduct for the use of Engineer Zone. This forum is intended to assist you in isolation and correction of issues but by tying up multiple threads with the same issue is inefficient. Please withdraw the posts and resubmit to a singular thread based on the most likely error candidate based on your own engineering judgement.
ADA4522 internal oscillator https://ez.analog.com/amplifiers/f/q-a/163131/ada4522-internal-oscillator
AD7616 internal oscillator https://ez.analog.com/data_converters/precision_adcs/f/q-a/163130/ad7616-internal-oscillator
AD7091-4 internal oscillator https://ez.analog.com/data_converters/precision_adcs/f/q-a/163129/ad7091-4-internal-oscillator