The middle spout is leaking

To tell you the truth, about all that you can do is swap a non leaking spigot stopper with one of the others and tie off the line of the leaking spigot. They don't seem to make the spigot internal stopper anymore (I can't find it) and I just tried to grind down the stopper arm to make a tighter seat and that doesn't work either. To take to top off, turn the bottle collar to loosen and then lift off, two screws in the top back corners and then the lid slides a little to the front to release, you can then see the inside where the spigots are. Where the stopper assembly arm goes into the spigot, that portion can be unscrewed and you can then see the internal spigot stopper,