After you move a camera - press 'Ctrl + Alt + Z' to undo the camera transform steps, and press 'Ctrl + Alt + Shift + Z' to redo the camera transform.

Due to limitation in blender, there is no option to know if the user grab and move the camera, or if the camera set in its place. to overcome this problem, the addon check if the camera transform is the same for X seconds (can be edit throw the addon pref, by default its 1.5 s), and when it have the same transform for X sec, its save its transform in the 'undo list', that way, if your grab your camera around it will not add its location to the 'undo list' until the camera will stop move for X sec.

There for, if you click and grab your camera, and keep it in the same location for X sec, it will save its location even if you didn't finish to move the camera.

And for the same reason, if you move your camera, and then move it again before the time pass, its location will not be store in the 'undo list'.

So its recommended to set this value not too high, so it will store the camera transform before you move it again, but not too low so it will not store the information while you still move the camera