Yes it was. If the money is owed PER the order in place at the time, it cannot be erased. But, if it was shown as owed by John T Smith, and was really owed by John B Smith, and CSE messed up, it can be erased from John T Smith, for example.
Or if a person claimed an arrearage, but the payor produces evidence that arrears was paid, the "claimed" arraerage can be erased because it had been proved to have been paid..
Or if Mary Smith in R.I. received all her ordered CS through RI CSE, but ALSO filed in a state in which she later lived, resulting in two simultaneous orders for the same children, the fraudulant "arrears" in the second state CAN be erased .