Anyone seen this message before?

Received packet on from relay agent
Tossing packet: Not a PXE packet

We have a location we are unable to image due to this message. Our network team is at a loss, as the requests are definitely coming from a PXE boot session. This environment is running ZEN 11.3.1. Other locations are able to image without problem, using other primary servers or satellites. This particular location images directly from the local Primary Server.