Yeah "notorious inconsistency issues in windows corners" almost feels like an oxymoron to me. Perhaps it is notorious among graphic designers, but I'm sure the vast majority of MacOS users will never notice or care.
To my designers eye it was the first thing I saw, to him it was nothing.
I still think it's bad and a sign of a change in apple focus/style, but it's clearly not an issue at all for a lot of people.
Said colleague did get cross when he struggled to resize a window though. Turns out inconsistent corners means inconsistent handles. And that is a real problem.