Still happens. I work in a codebase that is definitely on the upper end of complexity for the industry. ~18 months ago we hired a very smart developer who had one of the more rapid onboardings to our codebase I've seen, he was very productive in under a month. It turned out he was too productive and people were starting to find new layers being added to the code base. A few of the more senior folks had to come in and shut him down.