I suspect this is going to run into the same problem that other dual relay switches have. Smartthings needs a device handler that can recognize multiple controllers in one device. This comes up a lot with things like power strips where you’re supposed to be able to get the energy use for each plug, but smartthings may only see it as one reporter.
People have been trying for over year to get the Enerwave dual relay to work specifically to control a fan and a light, but without success.
Some community members have it working so that a single on command from smartthings turns on both, so the fan and light go on and off together, but it doesn’t sound like that’s what the original poster in this topic was looking for.
The following has discussion of dual relays:
@mattjfrank might know more.