A few moths ago I bought this car (2015 Subaru Outback) and don’t drive a lot. I’ve noticed that the coolant reservoir shows fluid disappearing. The day after I bought the car the reservoir was 99% empty.
Dealer pressure checked the system and said there was a 2 pound loss in 10 minutes, within their specs so no problem.
I can understand seeing the drop of coolant in the reservoir during a years time. I just watched the level drop in the past 488 miles. My Honda never sees a coolant loss nor did any other car I’ve owned that was in good working order.
The car was sold as Subaru Certified and I believe any found problem would / should be covered under warranty. Maybe the dealer just doesn’t want to find the leak?