Upon filing, refund changed and won't allow me to re-file. Is the software's mistake as I didn't change anything and the comparison of original to refile is identical

A small number of TurboTax users may experience issues with ReFiling their tax return using the feature within the software.

For this reason, you will be unable to use the ReFile feature to make any adjustments to your tax return. You will need to make the adjustment by signing in to your CRA My Account and doing it online, or by completing a T1-Adjustment form and mailing it into your Tax Centre.

See the CRA’s How to change your return page for how to make an adjustment online in your CRA My Account or by mail.