Really common on the pre-LCI models. Really heavily discussed. Can be so subtle you don't even know.
For the record a catch can (from new) will reduce it, but won't stop it, or fix it once you have it.
Subaru have used a can of intake cleaner every service for years. Looking like this is good practice on every direct injection engine. Fuel additives don't work because the fuel goes directly into the engine and not sprayed onto the valves (where the buildup is).
We had a club event with close to 20 cars. Only 1 person could notice anything was wrong. All (on the dyno) were down close to 20hp and blowing black smoke under load. Only proper fix is to get an intake blasting professionally done (~$400).
By the time you feel the hesitation you have a really big problem