Settings don't save

I have followed the steps but bot able to reproduce the issue.

I have also followed the steps and guidelines. According to the provided gif, you have not set the default url. Therefore, it is necessary to include both the default URL and title. If you only add the default title in the link field, your changes will not be saved.

But it's set to Optional and nothing indicates both fields must be filled.

Should be able to fill just one field.

this has nothing to do with paragraphs, it's how a link field works, it's the same on a node link field too. and yes, a url is required, you can't have a default value without that, just like you can't have a text format default value.