I have similar or same problem as you did. My touchscreen works is work properly sometimes (5% of time), has vertical and horizontal displacement (70% of time) and does not work at all (25% of time). Calibration did not solve the issue. The device switches between states randomly on keyboard slide in/out. I've examined the flex (disconnected and connected both connectors board-flex and flex- touchscreen), cleaned the touchscreen (once it was removed from the flex). I've noticed there is another thin flex on the sliding mechanism, which is in bad condition (the layers on this flex are separated). It seems its only purpose is to make galvanic connection (looks like RF interference precaution) between sliding part and the metal support, but I am not 100% sure. Do you know the purpose of this thin flex? Did you have mixed behavior as described above?