BGP session timers reset with neighbors during RE switchover even with NSR and GRES.
It is expected that the BGP session timers refresh when Routine Engine switchover performed with GRES/NSR. However, the session itself is not re-established; the routine table is intact. The peer side also shows proper timings of BGP session.
Do not confuse with BGP session timers when RE switchover performed with NSR/GRES. Check from peer side.