When you import transactions, they are not executed. They should instead appear in your transactions list at the state they were in when exported, and with their original date.
Also, when you import transactions, there is a count of transactions successfully imported and a count of total transactions read from a file. Any transactions that are already in your DB would fail to be reimported. Any DB errors would also cause a transaction to not be imported.
I would recommend that you first verify that the move transactions are not imported. If not, then there might be clues in your mySQL’s error.log file. The errors will also be written into your WordPress debug log if logging is enabled in
wp-config.php. The errors would be written at the moment you attempt the import. Could you please check?
Please let me know what you find.