They all have track numbers, however, each piece begins with track number 1 for movement 1. Each subsequent track in the piece is numbered sequentially as are the movements. The second piece begins with 1 again, the first movement. If I number the tracks 1-n where n is the last track of the last concerto the order is correct in playing now but that is not the way movements are numbered.
In Img-1 I have selected "All Albums". If I rt-clk on that and do an add to playing now, the order is as I first reported, all number ones are at the top, etc.
In Img-2 I have done what should be the equivalent but if I rt-clk on the full selection (rt. side) the concertos go into the now playing list correctly.
This is a bug at some level or at least a very strange design decision - but I do have a solution.