There are certain situations when REBOOT=ReallySuppress is not used and the system needs to reboot anyway. If a reboot is required by the Windows Installer (for example, situations with system files in memory), then the installed package may not work until the computer is restarted manually.
It might also be so that the Setup.exe for the admin image does not support REBOOT. In that case you would need to use MSIEXEC.EXE instead.
Jimmy Bergmark - JTB World
Website: http://www.jtbworld.com
Blog: http://blog.jtbworld.com
Jimmy Bergmark
JTB World - Software development and consulting for CAD and license usage reports
https://jtbworld.com