the result is always the same.
Are you sure about this?
Usually when there is an issue like this it is not exactly the
same. There will be slight differences between each iteration.
In %99.9 percent of the cases, it is a wiring issue.
The other portion being a bad glcd, but the bad glcds
are usually do to previous incorrect wiring.
Usually it is something simple, like mis connecting wires.
Post some clear closeup photos of your wiring as well as a wide
shot that shows all the wiring.
I will need to be able to see where all 13 wires are connected
to the GLCD and to which arduino pins.
Also, a video of the display during the diags might be helpful.