Creating a square. To cut

Ok , here is my problem. After a creating a set of coasters, with a square to cut out . When the laster cuts the shape . It is ment to be 100mm x 100mm, but when it cuts the shape , is 100mm x 80mm , not square . I have tried to resize . Its just not having it …can somebody help please …thankyou

You don’t mention your laser but check to see if you have rotary enabled in LightBurn. If so, disable and retry.