Got IRS CP11 notice about incorrect Social Security Tax

I recently got IRC CP11 notice claiming that social security tax excess withheld (schedule 3 line 11 - Excess social security and tier 1 RRTA tax withheld) was calculated incorrectly and therefore I owe ~2k

W2s were imported automatically (and double confirmed manually) so It's not the data entry error.

The question is - what can be the reason? Incorrect Turbotax calculations or employers put incorrect data on W2? 

Is it something Turbotax support is supposed to help with?

 

Thanks!

Max