There is a lack of clarity on the type of surveillance data on which the last observations were made.
At the limits of coverage range, typical monopulse radar returns will continue to give good range information but with increasing bearing uncertainty. This can lead to false indication of a turn manoeuvre. ADS-B on the other hand may give increasingly intermittent coverage as the limits of the receiver range are reached, but all data decoded will be good. Error correction ensures a very low probability of path-loss data corruption.
It is important to know which type of surveillance source gave indication of a turn in those final returns.