Also why the normal speed warning at 16:00 into the video when there is no crossing and the train slows and then uses fuel to speed up again?
The home signal at the junction with the North line is at Stop - almost certainly for an opposing movement to enter the North line.
The automatic (the 2nd automatic) before the home would have been at Medium Speed Warning (Red/Yellow) as there is only a short overlap between the home signal and the fouling point. In the old days the automatic before that (the 1st automatic) would have been at Reduce to Medium Speed, but this is frowned on these days. Instead that automatic shows Normal Speed Warning - as in the video.
There is very little difference in the actions required by the driver in the two aspect sequences. In the old aspect sequence they would have been required to brake from 160 km/h at the 1st automatic to 40 km/h (Medium Speed) at the 2nd. In the current aspect sequence they are required to brake from 160 km/h to 0 km/h (Stop). Meh. Particularly as they can release the brakes as soon as they see the 2nd automatic is not showing Stop.
The signalling is designed to work with TPWS - particularly overspeed traps. The Home signal has a 40 km/h overlap, and the automatic in the rear shows Medium Speed and has a 40 km/h overspeed trap. The distance between the automatic and the home is sufficient for the overspeed trap to stop a train from line speed (160 km/h) before fouling the other line.
You could eliminate the Medium Speed entirely. But that would require placing the Home somewhere near where the 2nd automatic is now, so that a train SPADing at 160 km/h would stop before the junction. The preceding signal would show, as now, Normal Speed Warning so that the action required of the driver would be exactly the same as the current set up. The big disadvantage with this approach is that the train would be stopped about a kilometre from the junction rather than at the junction. A tremendous waste of time starting from stop after crossing an opposing train.
This behaviour is typical of intermittent speed control systems. ETCS would eliminate this particular problem, but at a substantially increased cost. A simple ETCS would also add other problems unless you go for the expensive version.