I've found actively pausing a video before exiting seems to improve the accuracy of the resume point. I'm presuming this is because it fires a beacon on pause,

I've found actively pausing a video before exiting seems to improve the accuracy of the resume point. I'm presuming this is because it fires a beacon on pause, but only every X (10?, 30?) seconds on playback. Not had many issues with it completely forgetting where I am though (it does sometimes get confused as to which episode I watched last though).