Laccase USA 2011 Harvest

After botrytis comes laccase and other issues!  We have been monitoring the presence, or lack of, this creative oxidizing catalyst.  We have seen 2 instances of wine browning that showed a < 1 unit/ml count of laccase.  So whats going on? We suspect other enzymes at play here, which are not showing up on the laccase test, but are wreaking havoc on the wine.  We have seen the color literally drop out of the wine after 5 days on the bench.  We know that his reaction involves oxygen because the same wine in an inert environment is a lot more stable.