2016 XC90 T6 with 51k on it. Complete maintenance history and oil was changed regularly. Car was not beaten. Engine developed a knock that was reminiscent of a rod knock from when my SBC decided it had enough of my shenanigans. Knock was more noticeable when the engine was cold and really only on acceleration, but even when warm it could be heard. Much easier to hear on the passenger side.
Car is currently at the dealer. They initially said it was normal. Then I went down there and had the shop foreman get in the car while I drove it. Within 10 seconds, he said "I hear it" - which made me think "no ****, idiot". Their diagnosis is that something in cyl 1 and/or 2's valvetrain is wonky. They are waiting on info from VCNA because they've never seen a failure of this sort on these engines.
Anyway, thought I'd post here in case someone else is hearing a knock when cold. It's not normal.