I’ve seen this super fast white light myself about a month ago. I’m in Edmonton, Alberta. Just by chance I was on my deck looking S.E. on clear evening just after sunset. The bright light (around ISS magnitude) was travelling west to east about 40° above the horizon. Like everyone here, I have seen thousands of aircraft, satellites, space junk and the ISS etc. It was doing at least 3x the speed of the ISS on a similar path. I caught it around south and watched it disappear just above the eastern horizon and took about a minute.
I read this thread after I seen the event. Satellites can be very predictable. The only thing I could think of was maybe someone is shooting one-time flyby recon satellites from a parked orbit? Anyway, I am just guessing. It was very interesting.