Obviously a mistake by the grading co.
Another set that has always been a bit of a pet-peeve when it comes to how they are graded is the E285 Rittenhouse set. These cards were made with extra extensions on the top and bottom borders but I don't know how many I have seen that have been graded numerically with these extensions either completely or partially trimmed off.
The Simmons below is an example of a trimmed card, while the George Davis is as issued...
I'm not bashing either company as I have seen the trimmed ones in both SGC & PSA holders.