The problem is, when the light is turned off at the accessory switch and then turned on at the load switch, you have to then press the accessory switch to turn the light off. It seems that the main switch doesn’t communicate the off status with the accessory switch, so you then have to press the accessory switch one time to put it in the ON state and then again to actually shut the light off.
Can you clarify the issue you are noticing? I am having trouble envisioning this. The Load switch, physically, can control the light at any time, on or off, and truly is the only switch that physically can in a virtual 3-way.
Any circumstance where the accessory switch would need to be pressed to affect a change should be impossible as its only capability is sending a signal to the load switch.
Did you mean the load switch must be pressed? Is the problem that the accessory switch can’t turn the light off after the load switch turns it on? I could see that as a possible software miscue, and it better fits with the rest of the statement about not transmitting off status.
Have you tried associating the switches in both directions with the GC3? The GC3 apparently may not handle it the same as say a Minimote might.
If I set up the Z-wave network with a USB programmer, the associations work fine.
What USB Z-wave programmer are you using? Is it possible to try adding it to the GC3 network and simply using it to associate the switches? (like the minimote)