Document template checkbox data label

I added to a document template a checkbox, and when i edit a data label, it don’t save the new label. There’s anything i might need to edit additionally?

After edit the Data Label and save it, it return to the original value “Checkbox 1a31da89-4ae0-49…...”. I validated and i’m not using the Data Label anywhere. Any Data Label that i entered is reverted to the original value.