I had FSD 12.3.3 take me for a ride on some high speed rural highways. I quickly found a big problem with the V11 stack. On the two lane state highways I used, None of the 65 mph speed limit signs were recognized by the V11 stack.
I find that FSD switches to V11 stack at 65 mph outside of city limits in rural areas. While this does come with latency issues and you need to be very cautious for cross traffic and lead cars slowing to turn off the highway, prior to V12, FSD would read the speed limit signs and set the speed accordingly. While not perfect, it was pretty good at this.
Now, V12 seems to completely ignore the speed limit signs on these rural highways. It does switch back to V12 when the speed limit drops, as when entering a town, but once it switches to V11, it failed to perceive any speed limit signs. I watched as the car drove past many signs clearly displaying the 65 mph limit, but nothing was shown in the visualization and the speed limit sat at the last V12 read speed limit.
Of course, I was able to roll the speed up to correct this, but, it's curious that the car ignored all these signs. 65 mph was as high as the speed limit got on this test. Perhaps I'll get to try some 70 mph roads soon to see if it's just the 65 mph sign.
On the same drive, once the car entered an interstate, V11 read the signs correctly and set speed accordingly.
The V12 stack, of course, worked like a champ with nothing to do but watch in awe as Tesla makes something so difficult look so easy.