We are running around 150, 27" iMacs dual boot with Sierra 10.12.6, Windows 10 Enterprise and Bootrunner2.5.1.
All of our machines are imaged the same way with the same software.
Boot runner seems to fail here and there. Once it fails, the only way to make it load is to log on to the mac side and log off. Restarting the machine does not help.