This could be one of the transistors associated with this coil on the Solenoid Driver (SD) board on its way out.
You should check the CA3081 transistor array U chip, and the corresponding TIP102 transistor. I just fixed a problem on one of my games where the flippers would work before and after a game (ie. the flipper enable relay was always on). This ended up being a faulty CA3081 chip, replaced it, all good.