I would focus on the AC power side of things first. Are you using the same power strip (surge suppressor) also check your cords to make sure the grounding pins are present. You might also want to check the outlet which you are using is properly wired and grounded. I recommend this simple tool to check [https://www.lowes.com/pd/Southwire-AC-Tester-Analog-120-Volt-Test-Meter/1001005712|120-Volt Analog Receptacle Tester]
Also try a different MagSafe charger if you are not using the Displays MagSafe connection . Do you find the issue is when you use the displays connector or when you are using the chargers connection?