Well this is strange and probably proves that I have been an idiot somewhere along the line - but Marketo support set up the same sort of test as I have been running and all is working fine.
I ran my own tests again... and all is working fine i.e. I can no longer replicate the issue.
It looks like it's fixed now. You definitely weren't imagining things. I had to write a script just to fix our email preference centre because of it.
In fact the script is still relevant, with this, once you refresh the page, your prefill still remains. Also works if people navigate directly to the page rather than clicking an email link.
console.log(mktoPreFillFields) throws an error ReferenceError: mktoPreFillFields is not defined
I described it as not accessible as I wasn't sure that it hadn't been moved
I'm not sure if it's related but at some point in the last two weeks, our forms stopped displaying options based on a member status each person has. Regardless of member status, it only shows the options that should be displayed to non-members. I submitted a support case last week and they came back to me on Friday with the suggestion to turn off pre-fill. That didn't help my situation, but it leads me to believe Marketo was aware of the issue at least by then.
(Program) member status isn't something you can directly use in a form, so this doesn't sound related to Pre-Fill. Have you segmented the form on the LP?
We have a custom field for member status, which uses our custom membership codes. It (usually) works just fine. I should have just said I submitted a case for something else about a form and they seemed aware of the pre-fill issue at that time.
Hi folks, we had a support ticket come in for this but it was closed and the behavior was verified as working as designed. Please, please, please don't hesitate to continue to reach out to me directly if you still are experiencing any issues. We haven't been able to reproduce anything but this is a priority so don't be shy!