Register file:0x15--Receive Time Stamp accidently becomes zero

Hi:
when I statistics the data from cle about CCP, I find a strange thing.The CCP Rx TimeStamp should be form 0 to 17 seconds increase every 150ms。but In fact Rx timeStamp become zero at any time.Like:

Register file:0x15 convert RxTimeStamp to Time(Unit:seconds)
574db920a9 5.868235003
------------------------- -------------------------
598907dec9 6.018239867
------------------------- -------------------------
5bc4569afd 6.168244724
------------------------- -------------------------
5dffa5590e 6.318249588
------------------------- -------------------------
01d2b7e3f0 0.122543477
------------------------- -------------------------
040e06a223 0.272548342

Used value/(128*4.992x10E6)==>Conver to time

Normally,RxTimeStamp should increase to 17 seconds then becomes to 0.
why this error has occured?

Thanks!!

The advice would be to check if you are getting errors and do a soft or hard reset, in this case counter would restart from 0.