When there is water leaking from a light fixture in the ceiling you either have a roof leak or plumbing leak that needs to be fixed as soon as possible.
Roof leak water move around.
Identifying the cause.
Reasons for a roof leak on an external overhang.
Recaulk the corner flashing if any areas have hardened caulk.
Replace any missing or rotted siding above the step flashing on dormers.
Dormer walls provide lots of spots where water can dribble down and enter the roof.
Move the light up the roof and away from any drips to find where the water enters the attic at the dormer.
The drip is often.
The light reflects off the water as it enters the attic near the dormer.
Caulk can be old cracked or even missing between the corner boards and between window edges and siding.
A standard homeowners insurance policy will cover water damage and roof leaks unless they re the result of gross negligence on your part.
Both are definitely problems but right now you have an even more urgent one because a leak near a light fixture is a serious electrical hazard.
Often wind driven rain comes in from above the roof especially around windows between corner boards and siding and through cracks and knotholes in siding.
Even if the roof leak is caused by a windstorm or a tree.
A roof leak is always a cause for concern.