premise: It took crews around 2 hours to extinguish a fire Sunday morning at a barn on Routt County Road 18, near Stage Coach Reservoir. According to Steamboat Deputy Fire Chief Chuck Cerasoli the back of the barn and the roof of an attached outbuilding were on fire when crews arrived on scene around 7:30. Firefighters were able to limit damage to the buildings, but a number of vehicles being stored in the barn sustained significant damage. The cause of the fire has yet to be determined. Related
hypothesis: To this day, no one knows what caused the fires that caused major damage to vehicles stored in a barn on Routt County Road 18.
reason: It's not definitely correct or incorrect because we don't know if the cause of the fire has been determined yet.  The system may have been thrown off by the term "to this day"