re: Flickering Lights in fixtures

LED bulbs can do that, its a sign they are bad and you just replace the bulb

most dont realize they have power converters inside them to reduce voltage for the LEDs and that circuitry can and sometimes does malfunction

that said, i have seen older houses with attic wiring just twisted together with tape and not using wire nuts. often closing a door can cause lights to flicker in a house like that