When engraving to fill a shape, the marking can be delayed by the material or the geometry.
There is a setting called Scanning Offset to inform the engraver to start a little bit early. It is speed sensitive and you may need to develop your own settings.
This only affects the start and finish position of the engraved line (often left to right) and not the overall size.
Accidentally setting Kerf Offset in the Cut Settings Editor will offset all four lines of the square outward (or inward) but Kerf Offset will not change the engraved area.
Please post a picture of your current results so we can see what you’re seeing.