Stuck Mesh Vertex/ Vertex Won't Move

Hello - I initially posted this in the FAQ section, but figure it may help to post it on the General board too... Thanks - Jerry

I have setup a mesh grid, and in a view locations the vertex won't move with the other vertices that are in my list.

At first, I thought it wasn't welded, or simply not in my list of vertices that will be manipulated, but neither of these are true.

Is it possible to have a vertex become stuck or frozen?  See attached screenshot.

Any direction is appreciated.

Thanks,

Jerry