My 19CCD had a leak in that same spot while sitting on the dealer's lot before I bought it. The evidence was a water stained front curtain and right side bolster on the dinette.
When I saw this at delivery, I went crazy and had the dealer re-seal around the window on the right front (after removing the curved outer screen) and also re-seal the inside glass.
If you want to do it yourself, get some Acryl-R sealer for the outer seams (very fine nozzle like a small grease gun) and a tube of SikaFlex 21 for around the inside window. Remove as much of the old sealant as possible and then mask the areas you don't want the new sealant on. Both of these are on the Airstream store web site.
Either remove the mask quickly right after you apply the sealer or let it cure, score with a very sharp razor being careful not to cut into the aluminum, and the remove the tape.
Of course I re-did it after I got the A/S home as the techs at the dealer are less than expert at caulking!!!!! It's way easier than it sounds.....just be patient!!!!!
Lew Farber...RVIA Certified Master Tech...ABYC Certified Master Marine Electrician
SOLAR TECH ENERGY SYSTEMS, INC.
AM SOLAR ...MAGNUM…VICTRON ENERGY...LITHIUM & LIFELINE BATTERIES…MARINE REFRIGERATION