Can you be more specific on the slight shudder? Is it accompanied by a noise? Or just a shudder transmitted through the body. Can you feel it through the steering?
I've not had problems with CVs on my Carnival, but experience on previous vehicles has been that they generally make clicking or clanking noises when worn, and often only when at or near maximum angular displacement e.g. when turning at or near full lock.
A suggestion that worked on a previous vehicle that I suspected had CV problems was to drive slowly in circles in reverse at full lock. While noise from the CVs was almost imperceptible running forward, it was very noticeable in reverse. You just need a place to do it (empty carpark at night in my case).
I've had worn inner universals causing shudder on acceleration, but they also made a distinct click on acceleration & deceleration.
Did you try slow full lock turns, and in reverse, for any signs of CV problems? It would be worth also checking the inner universals for obvious wear/looseness. Otherwise, hard to say what it could be from the description.