Hi notaplanegeek,
Also one other thing which I cannot explain is that I was looking out the window in the cruise (I also noted this on a B777) and noticed a sharp vertical line of what looked like the difference between two mediums of air. About 20% chord, illusion? Maybe I'm not sure.
I've noticed the same effect in the cruise also. I thought it was the onset of a shock wave as explained in figure 7.1 of this document:
http://www.dept.aoe.vt.edu/~mason/Ma...Transonics.pdf