My 2018 Golf ACC doesn’t operate like this. It’s not the most intuitive system to set with different buttons for one mph and 10 mph (or is it 5?) increments and another button for the desired gap. Mine us not linked to speed signs or GPS and the set limit wouldn’t be exceeded without driver override.

Previous systems I have used were more basic but much simpler to use and remember.

Either the system in the original post is different to mine (for example if it’s a Mk 8) or it’s user error. If it’s the latter it may be they are adding one mph increments with the second button without realising.

Can self driving cars exhibit road rage??

Just wait and see ... :-)

My Ford acc works in the same way as others have said, staying at the set speed and keeps a safe distance from the car in front, it only speeds up when the road is clear or I indicate to change lanes on a motorway, however, my speed limiter reads traffic signs and adjusts to the limit, it will speed up again when it detects a higher limit sign, perhaps this is what the op is referring to

Yes, there is usually an option to have the car set the cruise speed to the limit the camera has seen,

It will take a very clever car to correctly interpret some of the road signs in this part of the world, as quite a few are disappearing into foliage while councils save money. I sometimes wonder whether that might be a valid defence in cases of speeding ?