Has anyone had problems with power steering on the Legacy?

Your car should still be under warranty so take it in to the dealer and let them fix it for free.

Something's wrong here, as very few humans have enough armstrong to drive a big-tired OB 10 miles.... On older models problem is always a worn belt that results in dangerously-intermittent function accompanied with squealing, OR cavitation at the upper return pump hose inlet's flattened small 0-ring causing foaming in the reservoir (surprisingly common).

I see now that you've a '14 Leg w/ unitized front belt, so it's not a worn belt or cavitation issue. You're probably under warranty, too, so get to a Subie dealer and let them scratch their collective noggins. Let me know what they find. Ern