Three client have received recent tax notices (CP-14) that the tax on Forms 8959 and/or 8960 were not computed properly.  These returns were e-filed and accepted back in March or April.   The IRS practitioner hotline could only tell me "it was not a math error, but a calculation error".

Another client recently received an unexpected refund.  Here the practitioner hotline said the Form 8960 tax was incorrect and they refunded all of the net investment income tax calculated on the return.

I believe the software calculations are correct.  Does anyone else have clients receiving CP-14 notices or unexpected refunds to do the IRS coming up with a different amount of Form 8959 or 8960 tax?