My firm's buyer bought this 1873 MS62 $20 Lib for $3,525 (first screenshot), sent it to CAC, requested a gold bean but got a mere green bean. I knew that there was something special about this coin (incredibly thick luster, shockingly few marks, original) but ended up flipping it for a whopping 10% profit -- and even that took seven months of shopping it around (LOL).
Someone a lot smarter than we were got it into a $31,725 MS64 slab (second screenshot). Ouch!
These events happened years ago and I suspect that the two people who will read this have had far bigger upgrade losses (even I have), but this one haunts me to this day because the under-grading was the most obvious that I have ever seen but I was too lazy to re-slab it. And how did JA miss it?
Thankfully, I am a retailer and thus do not need to rely on grading skills.