My 2015 Legacy has multiple HEHR flush window issues. I am in the process of replacing all the seals between the frame and the coach.
The factory used 1/2”material yet the flange is 3/4”. This discrepancy led to several areas not being sealed, especially the round corner Arches. I found what appears to be a good replacement gasket/seal at my local hardware store... and of course when I asked HEHR LCI) they told me it was up to the factory to pick the seal of choice.
The installation was fairly easy, and clearly far better than the factory install, and has solved at least 1 major water leak. I am now trying to figure out the best gasket approach between the tip up window in the frame, as I missing some gaskets, some are partial, and some are in place. Very inconsistent to say the least.