An 'Odds Updated' message on your bet card means that while the outcome you selected has been in your betslip, the odds for the selection have changed.
You will see a red down arrow if the odds have gone down (i.e. from 1.66 to 1.64) or a green up arrow if the odds have gone up (i.e. from 1.66 to 1.68).
You will be required to confirm that you accept the odds change, by clicking the ACCEPT button, before you can place the bet.