Problem with kernel panic when creating NetRestore image

Setup

Server:

Mac Mini 2011 model running 10.13.6

Machine to be imaged:

iMac 27 inch 2011 model.

Server and imaging target are on the same switch and subnet (all are on ethernet, no wireless)

Goal: clean install target machines with 10.13.6 using the NetRestore image

I have created a NetRestore image of High Sierra using SIU.

I booted the target by holding down that option key.

All our images came up.

Chose my NetRestore image.

It appears to be working I get the graphic with the progress bar and the little globe.

Partway through it fails with a (kernel?) panic and then quickly restarts.

Things I have tried:

Creating the NetRestore image on a different machine (another iMac)

Creating a NetRestore image

Installed clean 10.13.6 on an iMac and then booting that machine into target mode, and using it for the source of a NetRestore image

all produced the same result.