I guess I'm confused. I thought he meant that if he hooks up a 100W bulb at the switch as an additional load, either to the line or load side terminal, the dimmer works correctly and that putting the same light bulb on the load side of the fan control module doesn't fix anything. If that were the case, I'd suspect that some interference is messing with the signal between the controller and module in the fan that a light bulb is smoothing out. It would still be possible that something in the fan is the source of that interference - possibly some PCB for load control or fan control.
That is correct-- he says a load on the other switches in the box that have nothing to do with the fan , would allow the system to work when a load was on it. Sounds like the switch leg goes thru the maestro but he says no.
The 100 watt bulb at the fan location with the light to the fan disconnected will not work properly unless those other switches have a load. It is very strange- he says the bulb is 40 watt but did not check however with the fan light disconnected it would not matter as the pigtail had 100 watts.
This is why I said run a new temp circuit all the way and see what happens.