I think it's an omnipresent concern in people with 10-20% kidney function left, and outside that cohort, it's a concern if you're getting a supermajority of your calories from protein for a prolonged period of time (which is quite rare/expensive for most of us)

https://en.wikipedia.org/wiki/Protein_toxicity

Most people who eat "high protein diets" are not actually eating all that much protein, because their food is laced with lots of fat and some carbs. The guy eating burgers and sausage all day long is actually on a high-fat diet. This fools people because fat is so nutritionally dense, and because lean protein is basically always chock-full of bulky water. The soy "protein" I'm eating still has fat and carbs.