CaddCop
i have seen this issue, but when i start a video previously watched, i am typically able to click on the progress bar to move it back to the beginning... if that fails... Bentley stores "cookies" to keep track of how much of each video you have watched. i have successfully deleted my temporary internet files "cookies" and that makes Bentley's website think you have never watched a video and thus starts it from the beginning.
Brent