I am also experiencing this same issue...actually a client of mine originally reported the issue to me. As I investigated the issue, and experiencing the same issue as my client, I determined that this occurred with the update to 10.8.2. Downgrading to the previous version 10.8.1 corrected the issue for me. You can find it on this page? https://install.appcenter.ms/orgs/rdmacios-k2vy/apps/microsoft-remote-desktop-for-mac/distribution_groups/all-users-of-microsoft-remote-desktop-for-mac
I downloaded the 10.8.1 (2048), version immediately prior to 10.8.2 (2057), unzipped the package and placed the .app in the Applications folder (system not user). Connection returned to normal without the vertical bars.
Hoping Microsoft sees this and corrects the issue in the next update.
