You should see this change as you move closer or farther from the screen. Also you see this as you change the viewing angle from center to corners. There is nothing new here but since you can't control where people sit, the issue becomes one of educating people "how things work" all the way from what a LCD is to optics and how sight works.

Today you may encounter young buyers that expect 1 lumen consistency from edge to edge. May have to wait a few more years.

If you feel this was disconcerting, what did you feel about ratty old NTSC signal sets?