I had a similar experience once when attempting a crossover. I bought a 53T Satchel Paige in an SGC 4. I cracked it out (with some other key vintage cards), to send them to PSA. PSA sent it back with "evidence of trimming". Ok, so I sent it back to SGC (with the old SGC flip in the package). They slabbed it as Auth, with "Evidence of trimming"
Lesson learned, there's a risk in cracking any card, because 3rd party graders are very capable of making mistakes.