It is true. Happened to me 3 times! originally, i used the supplied double sides tape and that didn't work. Second time, i went with urethane glue that works with side skirts, and that didn't work. 3rd time, sanded down the glass to make better contact and again, it didn't work. Lucky for me, everytime i flew off, there was no car behind me.
I've had enough with it. As good as it looks, you just keep having the thought of it coming off.
Btw, the 3rd time i flew off, it got damaged in one of the corners when it landed. I just wish there was a better way for it to hold securely.
However, there is a member here or two that has had no problems with it at all.
Good luck