Software Deployment

Pardon the sketchy title....

I have a Managed Installation for Symantec Endpoint Protection.
It required a start /wait variable, so inside my SEP folder is a bat file that calls Setup.exe with the start /wait cmd.
It works fine it I run it locally.
It works fine as  Managed Installation to a remote target.
It works fine as a user download.
Exported to my K2000, it "tends" to work fine as a Post-Install task.

Here's the thing. I have three Dell 790s that I am currently imaging. The first one imaged fine, SEP installed, updates - no problems.
The second 790 I just imaged however, though the task list shows a green checkmark for a successful installation, on login, SEP is not installed.

Has anyone seen this before?

Our K2000 has recently been put onto our VLAN, images time for a basic Win10Enterprise with less than 10 software installations (browser, VLC, Office, SEP, etc) is about 40 minutes, so I don't think the process is timing out, but I don't know for sure. I do know that before my start /wait, the machine would move onto the next task and kill my SEP install.

Not sure what's going on here.