The fire has only crept south very slowly, whereas it's moved west to Malibu very rapidly.
I think it's safe to say that Riv is pretty far away from the active fire in terms of potential fuel (
edit: now that I see the line of trees along Capri Dr, I'm not so sure), and the conditions on the ground are certainly not the dry tinder that makes these fires so dangerous (the same reason no vineyards burned in the recent huge Sonoma County fires), but houses
are fuel, so anything is possible.
I think the evacuations are mainly for the very problems that Pacific Palisades faced, that the roads became impassible because of automobiles that were abandoned, which creates a cascade of impassible roads, preventing firefighters from stopping preventable damage.
Edit 2: note that Calabasas CC and the (illegally built) Perenchio three-hole course are both under evacuation warnings. Mountain Gate CC is currently the eastern edge of the evac zone, but not inside it.