so the online expert says it's not a strobe and tells us that its the wrong side to be a reflection from the Sun (which is clearly to the 9 0'clock of scene)....
Not sure how the above contradicts what I said? The aircraft as viewed is in shadow, and looking at the second aircraft (and photographs) there is no strobe in that location.
Actually, looking at the screen shot it looks more like a reflection from something on the far shore - car maybe?