Not quite what is meant by “flickering“ in the op, but I have been to a neighbors house about midnight and watched the LED can lights in the kitchen “flicker” and they were extremely dim. This is with ALL the lights off in the area.
electrician had been there numerous times. I looked in the panel and the piece of copper that runs from the ground bar to the neutral bar was loose. Tightened it, problem solved. Electrician called me and said he tightened everything in that box EXCEPT that factory installed copper jumper. Told me he won’t make that mistake again.