Prefilled form with wrong data

Such a large scale error seems odd to me. Usually when this happens it is because someone forwarded the email and Marketo saw the personalized link on a non cookied browser, filling in the other person's info.

I suggest you ask Support and see if you can collect a list of leads who were affected (or who called).

I have experienced this at a previous company and was not able to determine root cause. Seemed to happen erratically and couldn't be traced back to something like email forwards.

A couple of things come to mind:
1. Email Forwarding - Specifically check that you also did not receive any replies from the lead (or whoever created the email link).  If a lead responds an email you sent out and you receive that reply and click/copy on a link from within his cookied email, you will risk being cookied as that lead as well as using that lead's link in your email.

2. The actual link itself (is it a copied link from a real lead that is cookied?) - Send a copy of the email to yourself.  Click on the link and see if you can reproduce the issue.  If not, the issue is most probably not with the email you sent out.   If yes, the issue is the link itself; check this. 


 

The email address we send our Marketo campaigns from is a custom mailbox on our server that I only have access to. I create/design the email - I send myself a "Test" of course to verify, when all is good, I schedule the send to the list as required.  There is no forwarding, no link adjustments.  The email is an original for everyone, yet when one person clicks on the link to go to the landing page, some see info for someone who has already filled out the form at a completely different company.

Sorry - I am the original commentor - I have two instances I monitor, so I have answered your questions logged in from the other instance.