Mismeasured an entire crown molding run because of a 3 inch door stop

Last month I was doing a big install in a condo outside Nashville, and I had every angle marked and cut perfect for a dining room crown molding. I got to the last corner and it was off by a solid 3 inches, which made zero sense since I'd doubled checked everything twice. Turns out the homeowner had one of those industrial door stops screwed into the baseboard that was hiding a wonky wall, and I'd measured from the stop instead of the actual corner. I stood there staring at the gap for like five minutes before I noticed it, and I couldn't even be mad because it looked exactly like a normal stop. I ended up cutting a small filler piece and caulking the seam, but now I always walk the whole room and touch every protrusion before I pull out my tape. Has anyone else had a hidden trim or fixture throw off a measurement like that? What did you do about it besides swearing at the wall?