From December 2016 until February 2018 I dealt with the stalling issue. On cold days, when pulling up to the first stop of the day, the car would shudder, shake and ultimately stall. Oftentimes the check engine light would come on in response and trigger a cascade of unrelated warning lights and electrical subsystem failures. Each time I pulled and cleared an engine running lean code.

Several Subaru dealerships had no idea what was going on and since they couldn't replicate the issue, couldn’t do anything. Finally in February 2018 I tried a different Subaru dealership and the mechanic, over the phone, as soon as he heard the problem description said “Dude, you need new air intake manifold gaskets!”. At least he was right and this problem hasn’t recurred.