Venting bathroom fan into attic

Just replaced my master bathroom exhaust fan, and discovered that the old fan was simply connected to a short 3 or 4 foot run of Duravent-type flexible ductwork venting into the attic. The builder held the end of the duct up above the insulation with a harness screwed into the plywood roof deck. This is within about 5 feet of a soffit vent, and I see no evidence of mold or moisture damage. I went ahead and just connected the new fan to the same duct for now. My question is, I know it isn't recommended to vent into the attic - but is this a _code violation_? The house was built in the mid-90s but I just bought it last year. I'm surprised my home inspector didn't see it. House is in Kansas.