Thanks for replying Rico!
I did test the PCB beforehand and it worked fine. I do not have a multimeter so i haven't tried that yet. Although i've noticed something weird; after unplugging the keyboard, the shift key is still "stuck" around a 1 minut after on my laptop, but it goes away... This only happens when i connect the keyboard. I've also tried on a macbook, and the problem remains with the stuck shift and G-button.