Chosen Solution
2015 12 inch MacBook retina is showing thick purple bars on the screen when it is at certain positions/angles and is showing normal screen at other positions/angles. Rebooting and clearing NVRAM does not change it. The issues seems highly sensitive to the position of the screen, what angle it is at.
Everything else is functioning properly(keyboard, mouse, internet..etc) as far as I can tell.
It doesn’t look like a GPU issue but just to be on the safe side when the glitch appears try connecting your Mac to an external display/TV to get the confirmation that artifacts are limited to the screen. If that’s the case it might be the cable or the screen are failing and need to be replaced.
