As the title says I chased a leak coming from the light under the cabinet in the bathroom.
It only happened in heavy down pours. I started out sealing all the roof caulk on that side. Then I discovered the out side light only had a strip of caulk on the top of the lamp body. I removed the lamp & found NO sealant under the lamp around the hole for the wire or screws. The screws were rusted.
A little caulk & new screws & good to go. It may be worth your time to check your outside lamps. Water may be leaking in you don't see.
Dave