[quote="BaneI’ve never heard of that.[/quote]
You definitely have. It’s the same effect you can get when you put the microphone too close to the speaker playing back the sound of the microphone. But in your case there is clear delay between original signal and signal fed back to the original one. This means the loop is probably between Cubase and audio interface:
Cubase → audio interface → Cubase → audio interface → …
You may have configured your audio interface to send output signal back to Cubase and then in Cubase have monitor on in a track. This makes signal to bounce between Cubase and audio interface (a feedback loop).
You also may be using a delay plug-in with feedback set to >100%. Hard to tell where the problem really is. Just search any unusual settings on you signal path.