I don’t know if this is really a bug, but I give it a try.
It possible to (accidently) drag or place points outside of the drawing area, making them impossible to reach. The only way to get them vissible is to move the entire object.
I don’t know how the rest of the software deals with negative coordinates.
Maybe there should be a warning popup like “you are about to place points outside the visible area, are you sure?”