Over the years, the teak tire fades in thickness due to wind, weather and washing. This causes a plug, over a screw, to fall out as it has become too thin.
It has less impact on the shelf life of the tire, but it does not look so nice. But you can easily replace the old plug with a new one and get a nice tire again.
The best sailor greetings
Erik Sønderskov Jakobsen (HR 352, No. 637 ”Doris”)