Only the red pcb shows the outline of a cutout, the blue board only shows a top silk layer of a square shape the I drew around the cutout.
When viewing the board with cutout in easyeda software using the 2D or 3D viewer, you will see the background grid, as if it the are was really cut out of the pcb.
The red board is what appeared in the 3D view of easyEDA software, the blue image of the board is what appeared in the jlcpcb website after uploading the gerber file.
Thank,
TonyAm