DALI gateway problem

I have an issue with the DALI gateways and both 5753L and the 5753PEIRL . I have three office floors with all DALI fittings and sensors in the offices. Every now and again the c bus on command will be broadcast but the lights will not physically come on. It is on random floors in random offices at random times. It may be fine for three weeks and then I may have three in a day. Tech support have verified that the setup is right with the sensor but can't grasp the concept that while it works 95% of the time that 5% is unacceptable. Anyone had a problem like this?

 

Use the C-Bus Diagnostic software to verify that the message was received correctly on C-Bus. The easiest way is to set it logging and get someone to take note of when a failure occurs. Then look in the log at this time to see what happened.

Ideally you would need a similar tool for the DALI side to see whether a message was sent onto the DALI line.