I've owned 6 Subarus in the last 18 years. I noticed quite early that there was a tendency to overfill with engine oil at service time. When I first pointed this out to the then dealer, I was told to look on the bright side because I was getting more oil than I paid for! I asked them to drain the excess out of the engine and would not accept the work for payment until they had. The service manager told me that his technicians used pre-set auto delivery pumps and there wasn't a setting for the amount that Subaru specified - so they overfilled rather than underfilled. After this I have always specified in writing that the engine must not be overfilled and if underfilled slightly I would accept this and adjust the level myself. No doubt, this marked me as a total pain at the shop. I always check the oil level before I start my car.
My late Father in Law bought a '98 Outback Special and some while later, when he visited us in ME from upstate NY, I had the chance to drive it. After, I asked him if he found it sluggish and he said he had it back to the dealer who could find nothing wrong. I checked his engine oil and cold it was way above the hot level. Draining a lot of surplus oil to apply the correct measure transformed it and let it run much more freely. Thereafter he made the same requests as me of his dealer but later oil leaks revealed that the crankshaft oil seals were blowing and needed replacement. I agree with the earlier comment over filling is just as bad as underfilling.
My 2014 Crosstrek was not overfilled at new and hasn't yet reached 7500mls. My Wife has bought a 2014 Outback and it was overfilled at new; it will be attended to this week.