Bug in form scaling with FontAwesome.Sharp

Question

My project contains 2 Forms, one is the LoginForm, other is the MainForm The LoginForm will do this when login button is clicked and assume it is a successful login:

MainForm mainForm = new MainForm ();
this.Hide();
mainForm.ShowDialog();
this.Show();

This is my login form when I run the program (it is correct):

when I login, this is the MainForm:

it shrink, it should look like this:

then I hit the log out button from MainForm (it execute this.close()), the login form reappear, but now it is look like this:

way smaller and not even in the center of the desktop as I set them to be in properties. But somehow, my friend who ran the program on a 12.5 inch laptop (1366 x 768 resolution), all the things is perfectly fine, mine is 14 inch (1920 x 1080) get the above problems. The IconButton from FontAwesome cause this, it's all good after I remove all IconButton from the forms