Supposedly the noise goes away if you put a dummy load on the 5V line, but you'll never get a straight answer from anyone online as to how to go about that (don't ask me, nobody would tell me, either) because everyone assumes you'll kill yourself.
-- milkmilklemonade
I don't have one of these supplies so I can't speak to specifics of the noise problem, but a dummy load is just a big resistor from power to ground to ensure there's a minimum load on that rail by wasting a little energy as heat. As a wild ass guess based on that supply's specs (https://www.meanwell.com/productPdf.aspx?i=484 - 5V rail 5A, and they want 20%->1A minimum load) I'd probably start with a 10 ohm 50 watt (like https://www.amazon.com/LM-YN-Wirewound-Electronic-Industrial/dp/B071Z8B9FN) which will be a 0.5A load, and experiment from there with a second/third in parallel. The actual amount "required" will depend on the other 5V load in the system, and if it does help you'll want the smallest load that solves the problem, to minimize the wasted power/generated heat.