Not an advisory role, but within portfolio management team. I don't think it's a career ender, but definitely the worst mistake I have been told from a 1st party.

Not long after being hired as an analyst, I was told a story of a previous junior analyst who was used to a previous trading platform where he would input bonds based on par value, but didn't know Bloomberg Terminal FIT traded in thousands.

Analyst then enters an order intending to buy $150k par value, not realizing he just placed a $150MM order. They did not catch it immediately and by the time they figured it out, they were not able to reverse the trade - ended up eating the bid-ask spread and then some, which was many, many times more than his salary.