Mike on MSRC blog posted --"We’ve seen some questions from customers about some security updates that posted for a while today for Office for Mac that they didn’t see any security bulletins for.
I wanted to let you know that these weren’t security updates related to this month’s release or the two Word issues we’ve written about in Security Advisory 929433 and on our weblog: those investigations are still underway and we’ll release updates for those issues once we’ve met the appropriate quality bar. The updates posted in error were pre-release binaries that had been staged internally as part of our testing for an upcoming release. Due to human error, they were accidentally published to the public websites before our full testing release process was complete.
As soon as we discovered the error, we moved quickly to address it and remove the pre-release binaries from our public sites.
Once our investigation into this issue is complete and we have security updates that meet our quality bar for release, we’ll release those final security updates for all products affected along with a security bulletin. We’re also taking steps to ensure a mistake like this doesn’t happen again.
We recommend that anyone who may have installed these pre-release updates to uninstall them."
Accidental posting of pre-release security updates for Office for Mac