Be careful! What does your rundown time look like-50%N1 to 0% not using the gauge but monitor the starter gen flange? If low the prosedure is in the Trouble shoot manual to remove comp by comp to determine which one is limiting the free rotation. If none of them and in any case do a boroscope asap. There has been a case or 2 of carbon build up behind the injection wheel leading to no free rotation and obviously if not rectified big problems. If you are in sandy conditions there is a ASB to chk the vibration level due sand build up on the shaft.
This is just general as to little info.