Aeotec ZW116-B and a 2-way switch (not toggling)

Not really an Indigo issue (Everything works as expected from Indigo)

I can't get the ZW116 to work with a single 2-Way switch like the other modules I have (mainly Fibaro).

The light operates as expected from the switch. Flick switch down - light turns on. Flick switch up light turns off.

If I switch the light on from the physical switch and then turn it off from Indigo, I have to flick the switch twice (up and then down) to get it to come back on. In a nutshell, the module is mimicking the physical state of the switch (when operated from the switch). Is this expected from the 2-state setting?

All other (non ZW116) modules I have will toggle the light regardless of the physical switch state.

I have parameter 120 set to 1 (2-state switch mode). I've tried the 3-way switch mode also but this doesn't register anything from the physical switch. The Indigo device definition is fine, all settings are available from the device's configuration properties.

I'm wondering if I should be using the 3-state setting but it isn't working correctly (faulty device?)?

My failback plan is to read the raw Z-Wave command from the switch and create a trigger to toggle the light. This will work but isn't ideal as if Indigo is offline I can't turn on the light from the switch.

Pete