I had a bad leak on my 15 Anthem that was due to the Girard awning feet and anchoring screws pulling out of the fiberglass/wood roof. My coach was waterproof for about a year and ~ 12,000 miles and then developed a real big leak that was the exact opposite side as yours..... above the entrance door. I discovered that it was soaking all the insulation between the wall studs the whole way back behind the passenger seat (took of the light switch panels and everything was soaked inside the walls) and around the front of the coach to the first speaker mounted above the windshield.
To Entegra's credit, they diagnosed this as a much bigger problem than I did and asked me if I could detour to the factory which I did and the coach was in the shop for about 10 days, in their heavy rain simulator twice while they tore out the cabinets and the sheetrock around the door and the compartment above the door. They replaced the fiberglass insulation, the sheetrock and found the problem. The problem they were worried about most was mold buildup behind the sheet rock and cabinets and wanted to make sure that was perfectly dry before letting me go.
The problem was produced by the Girard mounting feet screws that had probably been overtightened when installed and the threads of the screws either pulled out right when they were installed, or vibration as the coach traveled made the front screws pull out or get loose and those holes then became the path for water to enter. My understanding was that you could not see the holes because the awning still appeared to be mounted solidly but that the bracket covered the problem. I dont know exactly what they did to solve the leak but assumed they used much larger screws to hold down the "foot" and then water sealed the whole issue. Problem never came back.
Of course, that is just one possibility in that general area (I think your coach has the "fake" awnings on the driver side so it could be the same issue).
Edit: the most common leak source over the years from 2014 to 2017 or so is a leak in the clearance lights on the front cap produced by a bad seal in mounting the lights (which usually are simply potted into the indentation with sealant. Sometimes the lenses crack and admit water and more often the seal develops a crack.... the usual diagnostic sign of this is that the water leaks down from one of the mounted speakers above the windshield).
Gary and Dee, Zowie and Bowie (traveling cat sibs)
2019 Cornerstone 45B, X15-605hp, Imperial, Spartan K3,
2013 Honda CR-V toad, Demco Excali-Bar II,
Demco Baseplate, Demco Toad Light system, 73 de W5Fi