I have given up on this issue. My FP2 (2016) always has a locked screen, which means it does not respond to any touch as soon as it is connected to a wall-plugged charger, with any charger, cable combination I have used. Not mine, not from various friends.
Yet another %#@* I have never experienced with any other phone I have ever owned - brought to you by Fairphone 
But I shall not only rant. What I do when I know I need to use the phone while charging:
- Connect to any PC or Laptop. Works 100% of the time, every time.
- I always have my portable powerbank with me because of that and I am also tired of buying new FP2 batteries every 6 months and resetting the phone’s battery management memory according to the #batteryguide every 2 weeks.
- Most moderately recent cars have a USB port nowadays. That also works.
- Connect to your TV or MediaCenter’s USB outlet. Has worked without fail.
I don’t even care anymore why this happens. I only know this happens exclusively with the FP2. Also its my second or third bottom module.
This is the powerbank. Got it as a advertisement gift at a security con years ago.
