Moving Notes In Edit Mode

Hi All,
In the edit mode, every now and then, when I copy a note or series of notes to relocate them, I sometimes barely move my mouse when the freaking note(s) just take off shooting 2 octaves either vertically up or down. It feels like if I didn’t quickly reverse the direction, it would have shot through the roof.
Knowing that this intermittently happens, I am careful about movement but sometimes it does it anyway.
Is this part of a feature I can turn off or is it a bug? It’s very frustrating. I thought it may be related to the zoom factor but it’s not consistent with that.
Thank for your thoughts.