Quoted from The_Director:

On my LAH I have a ball that is MIA that I have absolutely no idea where it is. I was playing and then started getting weird issues like when a trough switch isn't registering. I opened it up and saw only 5 balls in the trough, when I know there was six. I have looked up and down that entire machine and in the bottom of the cabinet and can't for life of me figure out what happened to that ball. I added a sixth ball to continue gameplay on it and all's been fine, but still don't know what happened to that thing. Looked under plastics, usually stuck ball places, literally everywhere! Anyone else ever had something like that happen?