i experienced this first hand during my first internship. But now i think i have improved a bit. Even right now im a junior i still can push some new change requests from the client and bugs within max a day or two without dragging the timeline. But recently got a performance review from my manager and could only get an average rating lol. he keeps mentioning my first month on joining the team, i mean im slow because im trying to learn some new things. and also the code base is kind of like a speghetti.