As built, the "Build" folder MSIs created by Creative Cloud Packager clobber the SCCM 2012 R2 client.  If installing the app from Software Center, Software Center exits at the end of the installation.  When installing as part of an OSD Task Sequence, the task sequence hangs forever on the installation step.

I tracked the problem down to MSIEXEC's Restart Manager which exits and restarts processes using files the installer needs to touch.  Restart Manager was shutting down the SCCM client and when it restarted, SCCM didn't know what to do.

The solution to this problem is to suppress reboots using

REBOOT=ReallySuppress

 as part of the command line calling MSIEXEC and to also pass along the property

MSIRESTARTMANAGERCONTROL=Disable

 which disables Restart Manager.  Once I did this, the MSI installed without trouble and SCCM worked correctly.  Software Center didn't crash and my task sequences moved on.