Thanks for reaching out, and thanks for using the BoldGrid WordPress Website Builder.
There’s a little bit of Custom CSS that comes with the built-in call-to-action that doesn’t get applied if you re-add the Call to Action in a new widget. Assuming that you’re still using the Visual Editor widget type that the original one was using, you can add this custom CSS back in Customize > Advanced > Custom JS & CSS:
background: unset !important;
border: unset !important;