Flickering display / powering off goes away with disconnection of magsafe

Prior to the El Capitan update my Thunderbolt display has suffered the none waking. I had the logic board replaced and everything was fine and dandy (after 2 visits to the Genuis Bar) up until the El Capitan update.

From that point forward my monitor would Flicker when it was being woken or just on its own. Whenever it felt like it. After taking it back to Apple and them telling me "there's nothing much else we can do but replace the LCD ($700+) or you can buy a new display". Wow.. Not even 2 years I've had this monitor and really?

Anyway this morning I plugged the monitor back in, and using it with my Macbook Pro Retina 15. Everything is fine and dandy up until my computer hit 100% charge for a bit, then the dreaded flicker (powering on and off). I disconnect the magsafe and thunderbolt connection, and reconnect both, still having the same ill effects.

Not until when I just plugged in the thunderbolt cable by itself did the monitor stay on fine. I then proceeded to plug in the magsafe charger and then it started fluttering/flickering again.

Disconnected the magsafe, good to go.

So.. What is this? Defective display or software not being able to cope with 100% charge and telling the display to stop charging without turning it off?