I had leakage right through the center seam under the solar panel
. The only way to see for certain where the leak was I had to remove the carpet on the ceiling. Could not see any defect or gap but water would drip out of the fiberglass. I had to remove the solar panel
to make this fix. The panel is held on with 6 screws that go up through the roof from inside. They have large flat heads with a screwdriver slot. There are captive nuts on the panel rails, lube them before trying to remove the screws. There is also a rubber grommet in the roof that the wire to the panel goes through. So your leak could be at any one of those points and caulking along the edge won't resolve the problem. I also had another leak in the seam forward of the roof vent. Leaks
at the windows
and marker lights
are also common, and rain can also blow in through the stove vent louvers.