Hello Mohammad
If we see one prefix in the database that is continuously changing the sequence number, then this means that for some reason, a route is flapping on the network. This is usually due to a routing loop that may occur not within an area, but via multipoint redistribution, that is, when a route is redistributed into another AS and then it is re-redistributed back into the original AS from another redistribution point. Solutions to such problems include route tagging which is explained further in this lesson:
I hope this has been helpful!
Laz