Have you come across this little gem of a bug when using Adobe Illustrator? You draw a box and apply a stroke to the inside of the frame, and the stroke appears to “float” off of the frame itself. As you can see in the image above, the actual frame object is the blue line, and my 1-pixel black stroke is way off. The bug has been around for a few years, and I’m not sure why Adobe hasn’t fixed it yet. Fortunately, the solution below fixes the problem.
When creating your document, click the Advanced tab at the bottom of the New Document dialog box. Untick the Align New Objects to Pixel Grid checkbox.