It doesn’t matter because it is under warrantee, but I think someone is CYA mode. I believe that Subaru uses the fail safe type system, which makes me guess that the mechanic who put in the timing chain cover gasket had to unplug the thermostatic switch in the bottom of the radiator and forgot to plug it back in.
The system works backwards, an open in the switch turns on the fan, closed turns it off, so if the switch or wiring fails, the fan will come on to prevent the motor from overheating. But the switch could have gotten damaged too, but I think the reset was just plugging it back in.