Welcome to the forum.
Sounds like a roof caulking issue from your description. Did you happen to take before and after photos of the roof? Did the dealer say what they did to 'fix' it?
Do you know when the unit was built to know long has it been leaking? The dealer or Jayco should check it for water damage in the walls and the floor.
Sherm & Terry w/rescue Eydie (min Schnauzer) & Charley (std Poodle)
2015 Jay Flight 27RLS (Nights Camped: 102 '15, 90 '16, 80 '17, 161 '18)
2006 Ford F350 6.0 PSD, 4WD, CC, LB, SRW, Camper pkg, Equal-i-zer, GY Endurance (E)