Definitely concerning to see the crook is perfecting his art.
Look at this example of the fake Bird/Johnson rookie
Here is the scan of the legitimate example. Notice the perforation alignment between the two cards:
It looks like the fake example was recently sold via an eBay auction. Here is the scan from the auction. The seller either purposely or accidentally didn't include the full holder in the scan. Notice how the perforation alignment matches the fake:
Example number 2 - Here is a scan of the fake Gary Carter rookie
Here is a scan of the legitimate version, notice the spot or break in the black line under the word Giants:
Here is a Probstein auction scan of the legitimate version:
Here is another Probstein auction scan of the fake version:
Regardless of whether the crook is fabricating his own cases or reusing PSA cases, the vast majority of collectors are unable to spot these. Buying from reputable dealers and avoiding cards at 60% value is good advice, but definitely not error-proof, as these cards are making their way into legitimate venues.