HI, If you choose feet or inches as model units in Options > Project Preferences > Working Units > Model Unit, the custom scales bar will be empty. In the US, these units are defaults, so you don't need to change them, just in case you would like to try with decimals.
This bug has been added to our Defect Database. It is planned to be fixed shortly. A possible workaround is to add the scales manually. Thanks,
