Board signals

Check the ground connection: you get that kind of wave when you have poor ground connection; I mean probe ground not connected or far from measuring point.

Another guess: are you driving that signal on long lines? If so, that ringing is present on the actual signal and you may need to put some termination to prevent it.

I see on the display DC full. If you are using a >100MHz oscilloscope, limit its channel bandwidth to 20MHz. No need to use full, since your probe would catch up a lot of noise, although I think this is not an issue here.