The Hirschbichl is a famous little pass between Weißbach near Lofer and Ramsau/Hintersee with some steep 30% slopes at both sides. My trip went from near Saalfelden, starting yesterday at 3:00 p.m. via Berchtesgaden, Zill (another nasty 25% of slope), Hallein, the Wiestal, Faistenau to Fuschl/See, arriving at darkness and cold, 80 km altogether, exhausted. I had some very small video camera with me and captured some sections of it.
The fork oscillation happened again when riding downhill from the Hirschbichl at some very steep section. I guess this is a matter of using rigid forks with strong brakes probably.