I had installed an aftermarket (TT) cross bar on my previous F800GS hoping for the same thing. It worked for me. Something like Barkbusters may also change the frequency because of the position of the bracing.
Naturally , I was just changing my oil last evening, so I had really started to worry. I never noticed a difference. It took fredz43 to make me relax a bit.
I had fitted a TT one on my previous F800GS to quell the throttle side vibration. Worked a treat. I moved it over to the Tenere simply because I got used to looking at it.