Yep....Same issue with mine. It moves around and flexes quite a bit. Great protection, but lots of movement. I took mine off for the summer and put the stocker back on. The V Stream may go up for sale and I'll try the Cal Science when the weather cools back down.
I'll throw in a couple thoughts, though this is one we'll never resolve. Stock shield was noisy and gave no protection. Got a California Scientific Tall and it was great for noise, buffeting, and wind/rain protection. Wish I still had it. Unfortunately, it didn't hold up the day I flipped and rolled that first FJR. So back to stock on the second bike, and added a V-Stream a few months back. Got a very good deal on a barely-used one, or I'd have gone CalSci for sure. I recommend you read
this if you're looking at changing shields. Mark at CalSci didn't just cut some plastic and put holes in the right places for an FJR; this is an aerodynamically designed and well thought out piece of work, and the link explains it. Beside which, SierraFJR and others around here, he's in West Sacramento and he's glad to let you mount it on your bike and take a ride. You'll be convinced. I swear I never heard my engine note at speed before or after I rode with the CalSci. And Bluesman's comment about the holes in the bottom of the screen are right. I wondered about those when I saw the CalSci, but the linked write up talks about those, and they
work.
Re the VStream, it's off now for the summer--it blocks TOO much wind, but I never had a shaking problem with it on my '05, either. (And FWIW, with the CalSci, I never needed to switch back and forth; lowered, it allowed a just fine airflow, even here in the hottest days.)