Two motion sensors two dimmers

[Plucker 0]

I have two motion sensors and two dimmers installed to control hall and landing lights.

 

I have successfully configured an association for the hall sensor and dimmer so that the lights come on at night when the motion sensor is triggered.

 

However, I cannot get the same to work for the other motion sensor and dimmer on the landing - the motion sensor is being activated but the dimmer isn't being activated.  The settings on both (set using Vera control panel) are identical:

 

Any ideas how I can get the second one working or is this a known limitation wth Fibaro devices?

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[Plucker 0]

After a little more experimentation I find that both motion sensors will control the hall lights but that neither of the motion sensors will control the landing lights so I am suspecting a defective fibaro dimmer on the landing - I have tried a full factory reset on it and the problem persists - no matter what I do a motion sensor associated with the dimmer will not control the dimmer.  I can control the dimmer from my Vera controller and from the physical light switches but the association just doesn't function at all.  Does anyone have any idea of what steps I could take next to troubleshoot this setup or should I just try and get a replacement dimmer?