Controlled lighting that subtly flickers when it should be off requires non-ghosting bulbs to fix the issue. Some games, most often Williams System 9, System 11, WPC, and DATA EAST machines, send a small amount of voltage to the socket, not enough to light an incandescent bulb, but enough for an LED.
These 1SMD non-ghosting bulbs are our standard recommendation to rectify this issue. They are a little more expensive, but contain a resistor that prevent small amounts of voltage from illuminating the bulb.
These bulbs have a slightly larger diameter than our standard bulbs. As such, they will not fit through smaller GI playfield holes, specifically in some 90s Gottlieb games, however they do not require non-ghosting bulbs for GI, so no issues there.
These will not however correct the controlled illumination flicker on Classic Bally or Classic Stern games, they require aftermarket lamp driver boards, or an adapter kit, to correct the issue.