OK........ this is the last thing I am posting today. It is not a "fix" per se but it is a solution
This is the "Vanish" save that was posted by dTurn after the lower right building vanished leaving only the rubble
At that point I simply pressed the
END GAME red arrow button
Then I went to the save game menu and started the
AUTOSAVED GAME
The autosave saved the game at the exact point I pressed the end game button so when the game started up it started the game up right at that exact point only now the building is back and the turn can be continued with the building restored