Program: 57998
Project: 57998
Buggy source:
@Override public boolean onCommand(final CommandCaller caller,final String[] args){
  final PlotPlayer plr=(PlotPlayer)caller.getSuperCaller();
  final Location loc=plr.getLocation();
  final Plot plot=MainUtil.getPlot(loc);
  if (plot == null) {
    return !sendMessage(plr,C.NOT_IN_PLOT);
  }
  if (!plot.hasOwner()) {
    MainUtil.sendMessage(plr,C.PLOT_UNOWNED);
    return false;
  }
  if (!plot.isOwner(plr.getUUID()) && !Permissions.hasPermission(plr,"String_Node_Str")) {
    MainUtil.sendMessage(plr,C.NO_PLOT_PERMS);
    return true;
  }
  UUID uuid;
  if (args[0].equalsIgnoreCase("String_Node_Str")) {
    uuid=DBFunc.everyone;
  }
 else {
    uuid=UUIDHandler.getUUID(args[0]);
  }
  if (uuid == null) {
    if (UUIDHandler.implementation instanceof SQLUUIDHandler) {
      MainUtil.sendMessage(plr,C.INVALID_PLAYER_WAIT,args[0]);
    }
 else {
      MainUtil.sendMessage(plr,C.INVALID_PLAYER,args[0]);
    }
    return false;
  }
  if (plot.isOwner(uuid)) {
    MainUtil.sendMessage(plr,C.ALREADY_OWNER);
    return false;
  }
  if (plot.getTrusted().contains(uuid)) {
    MainUtil.sendMessage(plr,C.ALREADY_ADDED);
    return false;
  }
  if (plot.removeMember(uuid)) {
    plot.addTrusted(uuid);
  }
 else {
    if (plot.getMembers().size() + plot.getTrusted().size() >= PS.get().getPlotWorld(plot.world).MAX_PLOT_MEMBERS) {
      MainUtil.sendMessage(plr,C.PLOT_MAX_MEMBERS);
      return false;
    }
    if (plot.getDenied().contains(uuid)) {
      plot.removeDenied(uuid);
    }
    plot.addTrusted(uuid);
  }
  EventUtil.manager.callTrusted(plr,plot,uuid,true);
  MainUtil.sendMessage(plr,C.TRUSTED_ADDED);
  return true;
}

Fixed version (ground truth):
@Override public boolean onCommand(final CommandCaller caller,final String[] args){
  final PlotPlayer plr=(PlotPlayer)caller.getSuperCaller();
  final Location loc=plr.getLocation();
  final Plot plot=MainUtil.getPlot(loc);
  if (plot == null) {
    return !sendMessage(plr,C.NOT_IN_PLOT);
  }
  if (!plot.hasOwner()) {
    MainUtil.sendMessage(plr,C.PLOT_UNOWNED);
    return false;
  }
  if (!plot.isOwner(plr.getUUID()) && !Permissions.hasPermission(plr,"String_Node_Str")) {
    MainUtil.sendMessage(plr,C.NO_PLOT_PERMS);
    return true;
  }
  UUID uuid;
  if (args[0].equalsIgnoreCase("String_Node_Str")) {
    uuid=DBFunc.everyone;
  }
 else {
    uuid=UUIDHandler.getUUID(args[0],null);
  }
  if (uuid == null) {
    if (UUIDHandler.implementation instanceof SQLUUIDHandler) {
      MainUtil.sendMessage(plr,C.INVALID_PLAYER_WAIT,args[0]);
    }
 else {
      MainUtil.sendMessage(plr,C.INVALID_PLAYER,args[0]);
    }
    return false;
  }
  if (plot.isOwner(uuid)) {
    MainUtil.sendMessage(plr,C.ALREADY_OWNER);
    return false;
  }
  if (plot.getTrusted().contains(uuid)) {
    MainUtil.sendMessage(plr,C.ALREADY_ADDED);
    return false;
  }
  if (plot.removeMember(uuid)) {
    plot.addTrusted(uuid);
  }
 else {
    if (plot.getMembers().size() + plot.getTrusted().size() >= PS.get().getPlotWorld(plot.world).MAX_PLOT_MEMBERS) {
      MainUtil.sendMessage(plr,C.PLOT_MAX_MEMBERS);
      return false;
    }
    if (plot.getDenied().contains(uuid)) {
      plot.removeDenied(uuid);
    }
    plot.addTrusted(uuid);
  }
  EventUtil.manager.callTrusted(plr,plot,uuid,true);
  MainUtil.sendMessage(plr,C.TRUSTED_ADDED);
  return true;
}