There appears to be a bug regarding the survey title and making it disappear. Currently, it wont disappear / changes font depending on whether the box for survey title is ticked in the appropriate location.
If nothing else is working, you can open the STYLE interface and scroll down to the bottom right corner of the preview screen. Click on the HTML/CSS EDITOR link. Open the CUSTOM HTML tab. Find the [template(“survey title”)] element and delete it. This will completely remove the title from your survey pages.
This fix is relatively permanent, although you can always add the element back in if/when necessary.
You might also want to report this problem as a bug to SurvetGizmo Support – https://community.surveygizmo.com/email-a-support-hero/