The best strategy continues to be what many of you already practice: diversify, focus on the long term, and allow for a margin of error in all of your investment decisions.
Theerror affected under 1% of the US debt being paid at the time, but interest rates on short term bonds rose nearly 1% in a short period because of that error.
They have offered for me to make a one-off lump sum payment to bring the account up to date or to extend my mortgage term, but this does not alter the fact that it is their error that will now impact on my finances.