I've created a CRED User form. It includes a single line input field (generic field). I've marked the field as required (see screenshot). When loading the form on the front-end, a "1" appears in the field (see screenshot). In the advanced mode of the form editor, I can see the issue:
For whatever reason, the "default" property is set to "1." The only way to fix this is to switch to advanced mode, which I would prefer to avoid, if possible.