After I bought S.Florida earlier this year I did download the Life Project and had the twin towers issue which I solved by deleting the Miami traffic folder as suggested. To the best of my knowledge I did not have the floating building at that time. When I noticed it yesterday I did try removing the Life Project folder in case that was the cause, but the building was still there.
It's not a big deal, I only see it if I land on 09 and look left as I roll out. If it was anything to do with the Life Project it would be worth it for the fantastic animation around Key West !
Interestingly, after the update I had no building elevations around Key West, but a re-download and reinstall did solve that.