What I also found is let your head be fluid with the ride and keep your glasses where you are looking direct through. A couple times I tilted my head down and looked out at more of an angle (like readers or bifocals) and I found the focus was off. Minute I moved head back up it was fine.
Yes, I noticed the same thing. Of course I also have bifocal (actually variable) glasses which makes it even more important to keep looking straight ahead. I also discovered that I had to keep my visual focus on "following the ride leader" to keep myself from becoming disoriented.