W2 shows employer withheld too much social security

My husbands job indicated that the original W2s they handed out were wrong as they determined they had withheld too much for social security.

 

They issued a new W2 but on the new one the Social Security $$ is the same amount as original. The only change is on the Medicare line where the amount amount went from $830 to $763

 

When I input the revised W2 turbo tax now say the employer owes me $296 as they over held social security and I should ask for an updated W2.

 

I will likely not receive an updated W2 by 4/18. Can i still file? This doesnt seem to impact the amount I owe to IRS in the end.

 

How is this handled?