1099R Box 7 Code 8 is this subject to penalty

My employer took out too much in my 401k plan.  They went $535.02 over.  They said I would have to submit a 1099R this year. 

The 1099R has arrived.  I see tax was taken from this amount.

In Box 7 of my 1099R I have a distribution code of 8.  I am younger than 59 years old.

Am I subject to a 10% penalty or a 30% penalty for early withdraw from my 401k plan even thought this was my employer's mistake?

Is Code 8 in Box 7 subject to any penalty (1099R).

Thanks,