My Dad has a 2019 Rebel and I asked him about if he had those cracks & he said no. Well, I stopped over there and took a look myself. He has 2 vertical cracks on both sides of the window frame. Now, that he is taking notice, there are water droplets and its leaking. He took it to the dealer today & showed them the Star bulletin and pics of the water leak. Service manager says he has only seen one other truck with this issue. Service manager is contacting Ram about next step. The 2019 is still under warranty with 6,500 miles. I'm not sure my Dad has ever opened that window. I think it is more about flex in the cab vs. the window bumping stops.
Hopefully, the 2021 Rebel that I am about to order has these water leaks squared away...although, after reading the history here, I am not so convinced.
Thanks for all the great info here!