According to Jim Trotter of Sports Illustrated, the Dallas Cowboys and Washington Redskins have both filed a complaint in federal court, likely to be heard by special master Stephen Burbank. This complaint arises out of the salary cap penalties imposed on the two teams for bonuses paid during the uncapped year. Of course, a) there were no rules that expressly forbid the actions of the Cowboys and Redskins, because that would have been collusion and it wouldn’t have really been the uncapped year that resulted from failure to reach a collective bargaining agreement, and b) the league approved the transactions at the time.
In other words, Dallas and Washington would appear to have pretty good cases. The union waived its right to claim collusion as part of the settlement process, but the teams can still point out the absurdity of what the NFL is now trying to pull off.