We’re having an issue where, if there’s conditional logic on the form, based on a dropdown, radio buttons, etc… and that conditional logic is applied to HTML fields or sections (but not products) (that we’ve tested so far), the signature field has a set width of zero in the div and canvas attributes, and in the inline CSS. The field appears as only the dotted field border, with no width.
after further testing, the sig field will show up correctly if it loads in after the rest of the form content (eg: if it’s triggered to show by a conditional somewhere else).
The Signature Add-On v4.2 which is available here https://www.gravityforms.com/my-account/downloads/ contains a fix for that issue. Please update your add-on to the latest version. You can use these steps to install after manually downloading the add-on: