There are two problems with the ransom drop-off at the bridge. J.R. positions himself on the far side of the bridge in order to keep surveillance of the pick-up. When Stanley drives up to the bridge he throws the package out of the passenger side window where it lands in the bottom, with the bridge between the package and J.R.'s position. When the kidnapper drives up to retrieve the package, he goes past where the package was dropped off, goes under the bridge, and collects the package which is now suddenly on the wrong side of the bridge. (If Stanley had driven toward the bridge from the other direction this problem wouldn't have occurred.)
What's more, when the kidnapper gets the package, the camera's POV (which should be the same as J.R.'s) is now in a radically different position, as if he had moved from his original location. Then the camera shows J.R. still in the same place he had been from the beginning. It's hard to understand how this sequence got so messed up.