Buying a Raw Card

[HoggieHunches]

Hi all--

I am somewhat vintage game. I am attempting to build a nice collection of White Sox & Bears HOFs. At the National, I purchased a raw Piedmont T206 Eddie Collins from a vendor who dealt exclusively with vintage (won't disclose name until getting feedback on here). Card looked to be in pretty good condition. He said he thought it was a minimum SGC 3 so paid accordingly.

I just got the card back from SGC and it came back "AUTHENTIC Minimum Size Not Met". This means evidence of trimming/altering, right? Is this common with these cards? Is it a "buyer beware" thing when buying raw? I am bit peeved but maybe I shouldn't be?