I strongly suspect a problem on the backlight control for the ESPLORA TFT plug in board (labelled "ROBOT LCD") sold for example at Farnell
I see 2 issues:
1- the Backlight is always ON because the P-channel MOSFET is not properly wired, Source and Drain should be inverted. Note that the distributed schematics use a N-channel symbol, when a P-channel is required, listed and mounted on the boards I got. This symbol inversion might be the root cause of the error.
2- R1, the current limiting diode is 200 ohms, which gives a LED current less than 10mA and a very dim display. The LED recommended current is 30mA. I computed and mounted 68 ohms for a much better brightness.
Both issue are critical for me. For example, controlling the backlight ON/OFF was the only way I found to have a clean blinking text message on dark background, as: - the display does not have double buffering (where you write one page, you display the previous one) - switching the display OFF results in a blank WHITE screen, when I need a dark text background.
May be other users can confirm my findings.
Otherwise, thanks to the Arduino community for all the efforts