Question about Cisco router

During testing, we observed that if the OSPF test tool send the LSU
with the mismatch LS Seq (the LS Seq number of the LSA in the message
is less recent than the peer Cisco router LSA database copy, the Cisco
router is change the neighbor state(OSPF test tool) from FULL to
EXSTART and send the init DD to OSPF test tool to put the its neighbor
(Cisco router) state to EXSTART to re-sync LSA DB again.
Could some one verify this behavior of Cisco router ?

Thanks,
Regards,
Nick V.

t2000vuong@yahoo.com