RED 15w detected as rogue dhcp server on WAN uplink

I'm deploying our first RED, a 15w.  It has worked all over - my home, coworkers' homes, etc.

However we have a problem where we need it to work:

The County Health Department has nurses onsite at the local high school.  Those nurses are County employees, and I want to extend the County's private network to them @ the school.

When I plug in the RED 15w at the school, the tunnel comes up and all 4 lights are green - wonderful!  Then the WAN uplink port shuts down.

Here is what we found when we looked at the logs in the school's LAN switch:

>>DHCP Violation Occurred. Disabling port 32 temporarily

>>A Rogue DHCP Server with IP of 10.170.1.1 was detected on port 32

10.170.1.0/24 is the subnet I setup in UTM for this device.

Why is the DHCP Server for my remote/secure/tunneled Standard/Unified RED 15w LAN visible on the RED 15w's WAN port, to where the uplink device on the host LAN can detect it?

I never would have guessed the DHCP process in UTM for this RED would be visible to the RED's host network like that.  How can I fix it on the UTM side I wonder?

Worst case scenario:  I ask the school's IT to disable DHCP Server violation detection on the RED's uplink port.

Thanks!