Yes. In my first DDR I didn't know how to do it. No guidance at all.
Flagged a key license as provided, while target hadn't taken it (was dumb to rely on IRL and agree that if they say provided that means it's there and I am the stupid one who can't find it.).
I still shiver while issuing a DDR thinking if I have made any stupid mistakes or missed something.
Really nervous, shivers.

Got the firm fired. I left/resigned. Partner somehow got the client back saying I have been fired. Called the client and told him I left on my own and that the Partner would never fire me. Joined a litigation senior afterwards. Now running my own business. Sometimes I struggle to make ends meet. But that's life. Take it head on as it comes. Have fun and brag about it. As far as I remember, the client seemed impressed when I told him that.

My first DD at a tier 1 firm. I did not review the miscellaneous clause of a sale agreement. Just before DD report was to be issued, i read that sale deed again to realize it has a ROFO clause in miscellaneous section. Told my SA who thrashed me, but did not highlight to the partner that i made this mistake.

It was my first DD assignment. I was lodged in one of those premium hotels with a fully stocked minibar. A wonderfully bright idea of celebrating the fact that I had made it and had come of age was conceived. This was the night before the actual DD started. Went out and got myself euphorically buzzed. I tumbled back to my hotel room and polished off the entire minibar.
By the time I was done, my sanity was left far behind and the world around me felt like a pulsating beast. Soon this euphoria turned into a barf fest followed by the Great Blank. It was only on account of my extreme dehydration that I woke up only to find my cell phone dead and the clock ticking at midday.
Rushed to the data room with my senior emanating that disgust-filled death gaze. Could barely look at the document forget about taking notes. When I reached my hotel, a similar disgust-filled death gaze from the Manager and the housekeeping staff welcomed me. I had to pay around 25K towards the refurbishment cost/penalty before I was asked to vacate the premise on account of the sudden unavailability of any room at that point in time.
That 25K credit card debt along with the applicable interest was nursed by yours truly for another 4 months i.e., the time I took to find another job. I guess it's water under the bridge now and I seem to have fully recovered from that incident emotionally, however, as far as my CIBIL score is concerned, that perhaps is a story reserved for some different thread.

There was none. The only conversation that I had was with the firm's HR. I can clearly recall phrases/words like "future prospect", "dim", "reputational risk" floating around, but clearly, at that point of time I was too brain-damaged to grasp the consequence of that soliloquy.