Make sure Auto Sync is off.
At the bottom of the right panel, there are two buttons: Sync/Auto Sync and Sync Settings. The first button switches between Sync and Auto Sync based on the little switch on its left edge. In the up position it is on Auto Sync. When it is on the down you are in Sync mode. When you have Auto Sync on, any changes you make to a single file are automatically synced to all other selected file (thus all images in Survey view).
Ok it works fine in the Survey mode (N), put usualy I use it in the second monitor (Shift N) and for me it didn´t work.