It’s hard to sound or be humble when saying, “I’ve got some constructive feedback for you.” This sounds like you’re saying that you know a truth that the other person doesn’t know, and you’re going to tell them this truth. It’s sort of like saying, “You have a problem, I’m going to tell you what it is, and you’re going to fix it. And moreover, you’re gonna like fixing it.”
Kim Scott writes about the problems with “Constructive Feedback.” (h/t Simon).
If you’re looking for a follow-up read, this piece about giving high performers feedback has been helpful.