For other EZxx devices, when you establish a link to a particular input or output, that suppresses the Broadcast message for that input or output. Would expect the same thing here but cannot confirm that with direct experience.

The Insteon Traffic tab of the SHN Utility is not a generalized Insteon traffic trace. It shows only specific commands issued by the Utility and the response to those commands.

You mentioned that the ISY established responder links for each of the Zones when the EZFlora was initially added to the ISY. Are those responder link records displayed by the Utility under Manage Device Links tab, Display Existing Link Records button?

Lets verify the basics first. Using the SHN Utility you can connect through a PLC and interact with the EZFlora. That sounds true as you are displaying the link database using the Utility. When using the Utility to display the link database are you seeing any Insteon traffic in the SDM window, not the Utility Insteon Traffic tab. Obviously traffic is flowing so if messages are not being traced by SDM we need to resolve that first. If traffic is not seen, establish a link from your KeypadLinc to Zone 1 of the EZFlora using the Set button technique. Don’t write the records using the SHN Utility. Establishing the link using KPL and EZFora hardware will do two things. The PLC has to understand that the KPL and EZFlora Insteon addresses are on your local network before it will trace messages for them. Establishing a link with the native hardware (KPL button press for 10 seconds, EZFlora Set button response with Set button taps that match the Zone number) will establish the addresses with the PLC and it will establish a working link between the KPL and EZFlora. Once that link is established between the KPL and EZFlora, you can use the Utility to query the Zone state as you press the KPL button ON and OFF to verify that a Zone can be controlled. Once that is confirmed then the Utility Manage Device LInks can be used to display the link database in the EZFlora to see if the KPL to EZFlora link can be seen. There is a potential mismatch with the link database address being used by the hardware established links versus the links being displayed and written by the Utility. Establishing a working link between the KPL and the EZFlora using only hardware and then trying to display that link will establish if the EZFlora is using a higher address for the link database. It also insures the PLC knows of the device addresses involved and should allow SDM to trace the Insteon message traffic.