shorted 0.05uF wired across the switch.
cut one leg of the cap off and see if it goes away.
I well adjusted pop bumper does not really need the cap. You only have to add it back in if you find the pop not responsive enough or it is missing scoring points.
If you want to replace the cap. Use a nice ceramic 0.047uF 100v+ rated cap. Vibration or voltage spike kills these caps.