I have 2. Both look like they made payoffs, which resulted in a few cents balance for some reason, then the adjustment eliminated that balance.
I searched my history for these "Principal Adjustment"s, and none occurred prior to today, so seems like something new.
2367276 Sep-15-2009 Dec-27-2010 Adjust 1 Paid $0.12 - - - $0.12 $0.00
5105519 Sep-15-2009 Sep-15-2009 Automatic Paid $1.79 - - $0.03 $1.77 $0.12
2367309 Jun-05-2009 Dec-27-2010 Adjust 1 Paid $0.11 - - - $0.11 $0.00
4870536 Jun-05-2009 Jun-05-2009 Manual Paid $2.38 - - $0.01 $2.36 $0.11