This line "[scenes objectAtIndex:0]" might need to add safety check, since "scenes" might return as nil or empty array. So in this case, "windows" will return as nil.

Anyone knows this status? Have some crash but cannot symbolicate with dSYM file. Thanks.

Seems like this "x, y" position is good info that "navigationAction" should provide. Maybe adding customized javascript code to capture that to be sure.