But rarely so. And the degree with which these sorts of surprises occurs with PGX graded books is multiples higher than the degree seen with CGC and CBCS graded books together.
I have bught 1 PGX slab off ebay. An ASM Annual 1, back in 2015 right around when the Sinister Six was slated to be the focus of the next Spidey film. It was a PGX 5.0, cant remember the PQ designation but the grade was off by at least a full point; just by ;looking at the book wihout cracking it.
Anyway, it was priced at around 50% off Overstreet VG/FN, back when the book was selling for double Overstreet.
I got $550 + shipping or so for it via eBay BIN, to a Canadian buyer...who in turn had to pay something like $75 in customs fee. I felt bad for that buyer.