Being over-prepared killed my interview and I only understood why about a week later

I spent three weeks preparing for this interview. Not casually, like actually intensely. I had written out answers to every behavioral question I could find, practiced them out loud, timed myself, ref

I spent three weeks preparing for this interview. Not casually, like actually intensely. I had written out answers to every behavioral question I could find, practiced them out loud, timed myself, refined the wording. By the day of the interview I had probably rehearsed 40+ responses until they felt natural. Or what I thought was natural. The interview started fine. First two questions I answered smoothly, good structure, relevant examples, appropriate length. I was feeling pretty confident. Then the interviewer paused after my second answer and said something I wasn't expecting. She said "that's a very polished answer, can you tell me what actually went wrong in that situation." Not aggressively, just curious. And I froze for a second because my rehearsed version had kind of glossed over the messy parts to make the story arc cleaner. I recovered okay but the dynamic had shifted. She started asking more follow up questions that pushed past the surface of my prepared answers, and every time she did I could feel myself reaching for the next scripted thing instead of just talking. At one point she asked me something completley off my list and I answered it fine, probably my best moment in the whole interview, but by then I think the impression was already set. I didn't get the role. The feedback through the recruiter was vague but included the phrase "didn't feel like a natural conversationalist" which honestly stung because I am one, just aparently not when I'm performing a carefully rehearsed version of myself. What I think happened is that over-preparation made me optimise for sounding good rather then being real. The answers were technically correct but they had no rough edges, and rough edges are apparently what makes you sound like an actual human who lived through something rather then someone reciting a highlight reel. Has anyone else over-engineered their prep to the point where it backfired? I'm curious if this is more common then I think.