We've had a small leak in those windows before too. Fortunately ours had a tattle tail and a tiny drip of water was noticed. Now, I seal all the way around the outside frame, and also seal the glass portion where it meets the frame. No need to just do the top and sides on these types of windows. No problems since doing that on the last several rigs.
John and Rebecca Dickson
Emma-8 / Little John-5 / Iva-1+
2013 Ford F-350 Lariat FX4, CC LB PSD, DRW
2015 Jayco Jay Flight 28BHBE (#8)