I have discovered several leaks underneath the teak decking and the cure is fairly simple. If you inspect the caulking closely, every so often you will find a small length of caulking of approx 2 inches which also may have started to lift at the edges. Underneath these strips is a small hole that goes completely through the deck. You need to locate the hole nearest to the leak and you should find that the teak has lifted slightly and the water is running under the teak and down the hole. Just seal the small hole and replace the caulking you removed.