Thank you @mbrandao for reporting this! Yes, we experienced the same thing after some additional testing.
However, I have some great news! Our awesome development team has deployed a patch for this issue that should allow users to begin using the feature normally again on Chrome 56. The only part of the UI where this might still be iffy is in Alerts - but that should be fixed as well when Chrome 57 is released.
Thank you all for your patience, and for the great information you provided! If you continue to run into trouble using the Switch Account menu, be sure to post here.