The single satellite ``location'' measurements that they are doing will not be able to tell that the last couple of pings were from the same location.
They will just tell us that they were from about the same distance from the satellite, i.e. on the same concentric angle circle, e.g. the 40 degree circle.
If this happened then landing (on land or in the sea) may be one explanation. Another might be that the plane's path turned to be more around or tangential to the circles, rather than perpendicular.