Tran1 reads the value of object X (500) at time t1, writes a new value at a later time, and then rolls back its changes at time t6. Tran2 reads the value of X (600) at time t5, writes a new value, and commits its changes at time t8. This scenario violates the isolation property of database transactions since Tran2 read X after it was updated by Tran1, but before Tran1's changes were rolled back, resulting in an inconsistent view of the data.