Mismatch of data from sales & reviews files

I have added the reviews file data table to the sales file data table to get a combined data table attached in the screenshot. I have matched the data based on the transaction ID column. When I matched the data based on the transaction ID, why I am getting differnt Audiobook names from the sales data table & reviews data table? The audiobook names should be same for the both data tables, if it has a unique transaction ID!