Hi Leah, you might want to check that your team is aware to not distribute a link that's already cookied, such as one that they received in an email. This could cause the form to be prefilled with the original recipient's information.
Similar to Haven's suggestion, if it's just one landing page that you're currently having an issue with, you can disable form prefill for just that page. Go to Edit the landing page, select Landing Page Actions > Edit Form Settings, and uncheck the box.
then....