Yes, today would be a great example. It did not show at 5pm on my end either. But the surge at 6pm was incredible, I spotted 3.5 in soma (3.7 off the coast, but come on, who are they kidding) and it was consistent for me well into the 8 'o'clock hour. Not enough cars showing on the pax app eventhough it was rush hour. Less cars, servers were able to display surge.
Giants game tonight, yes the surge disappeared in the middle of the 9th, and reappeared about 5 min after the game let out. Started at 1.4, 1.5, 1.8, 2.2, 2.1 (I went online at 2.1). Surge was not showing on partner app. Why? Because the amount of cars available was still high, the surge was localized in soma, but there were still cars available in fidi.
Although, there's times when surge doesn't show and I'll restart the partner app, and wala. But if I continue to zoom in or move the map around, I lose the surge signal again. I don't have this problem with lyft btw (but lyft has problems of its own with so called mini surges than never appear on the map. I spotted a 200% in mountain view that would not show on the map).
It seems the surge shows when there are less cars available. That's why the 2am surge shows consistently for me, not enough cars overloading servers.
But it's just a theory.