Someone, we won't name names, thought the J channel would be better off attached to the window frame and not the Tyvek wrapped OSB. He was adamant that his way would work best despite repeated warnings and orders to put the hammer down. Here are the results.
So, we fixed it. More of that silver tape from the top of the window all the way down the side of the window frame. We got lucky. The glass didn't shatter, the frame wasn't damaged more, and we didn't have to replace the whole window which would have been very, very pricey. Lesson learned by all.