I'm trying to escalate this with the support team, don't give up! I think there are several Marketo customers being affected but not everyone has noticed the increase in unknown location data.
Finally heard back, this is Marketo Support's response
Reading up on the engineering case to address the inferred data entering Marketo as unknown, our operations and product engineering team are currently working on a patch to address the issue. We have entered a blackout period (Nov 5, 2019 - Jan 1, 2020), meaning that most changes to customer-facing systems are restricted in order to ensure system / platform perform performance. That said, our engineering team expects the patch would be available in January 2020.
However, since this issue is impacting multiple customers marketing efforts we are making the case to senior leadership and engineering that releasing the patch is mission critical in hopes to have it released before Jan 2020.
A date on when this can be expected has not been provided so I am reaching out to a few internal resources to gather more information on when we can expect the patch to be released. When I receive any additional information, I will pass it along to your team.
We are having issues too, I was wondering why I'm suddenly seeing "unknown" for inferred fields. Hoping they can fix sooner than later.