Be careful giving feedback to people who don’t report to you

At one level, I think we all need to get better at giving specific, regular, behaviour based, feedback. But, we need to be careful that on doing so, we don’t undermine our peers, by encouraging their people to do things that they’re not meant to do.
So, instead, it might look something like… “Hey, I really appreciated when you [describe the ACTION you observed]. Is that what Ben (your manager) wanted you to do?”
They might say, “Yeah!” So you can say, “Great,”
They might say, “Actually, no… I think he wanted something different.” So you can say, “Well, it would be worth going back to Ben and making sure you understand WHY he wanted something different.”
They might say, “Actually, I don’t know.” So you can say, “Well, there were certainly some positives there, but it would be worth getting some specific feedback from Ben, heh?”
So, there… Feedback and keeping your team members first.