Additional workaround: You can also clear the checkbox and have the changes save for the defaults by editing an additional field's default in conjunction with it.

For example:

If I have a list with the text field called "Full Name" and a boolean checkbox for another field that I originally set as TRUE, I can clear the checkbox AND also update the other field's default, essentially doing two changes, then click Save Defaults.

The end result is that the checkbox says cleared and the default value becomes "NONE" for the boolean value and the field called "Full Name" has a new default set for it. After you do this, you can re-edit that other field to put things back.

Additionally, it appears that if you try to use the Save Defaults option by clearing all of the fields, it doesn't allow you to clear it. This might actually be by design, forcing you to have to use the Clear Defaults button.

I'll get this checked as well.

Regards,

Jon