Very simple steps as below,
1. Create table with 1 region
2. Insert 1 record
3. Flush the table
4. Scan table and observe timestamp of the inserted row
5. Insert same row key with same timestamp as previously inserted but with different value
6. Kill -9 RS where table region is online
7. Start RS
Scan the table and check the result, latest cell must be returned.
Thanks Y. SREENIVASULU REDDY for finding this issue.