I assume we have a bad solder point.
If you can solder, simply refresh the pins from the bottom of the PCB at the Pi’s location (not the LCD). Try and allow the solder to flow in the solder hole of the pin by holding the PCB flat with the solder points facing upwards and simply reheating for 3-4 seconds with a fine soldering tip each pin.
This soldering technique even though it saves space, it caused many issues as some points appeared ok with continuity test before shipping. When the PCB was designed Raspberry Pi Foundation offered Zero W without the headers which made this soldering method very easy. After some months RPi Zero W was only available with the headers presoldered but we thought we could get away with it