Taint was a faulty concept from the start and a way to attack bitcoin. Your bitcoin was "dirty" going to FixedFloat because that was in their best interest. Going out from FixedFloat to a different customer, that same bitcoin turns "clean" because again that's in their interest. Miracles happen every day in Bitcoin.
Everyone knows that and they are still pretending like everything with AML crap is fine 
I guess only way this coins trigger alerts again is if huge amount coins would go through their address.
Only government have the ''license'' to magically make Bitcoin ''clean'' with unlimited amounts, or should I say up to 21 million BTC.