AS3 drag and drop - weird behavior

I'm using AS3. I have a timeline with 12 labeled frames (page 1...page12). On frames 1 to 10, I have 3 objects that users can drag and drop onto matching places. There is a timer (60 seconds) and a counter. Users should match 15 objects correctly. If so, they go to frame 12 (congratulations!). If not, they go to frame 11 (Sorry, try again), which returns them to frame 1 (page 1).

ISSUE

When users drag an object (mouseDown) and don't release it when time is over, the dragged object remains on the screen. When users go to frame 11 and game starts over, the object remains throughout the entire game.

How can I get rid of the dragged object that isn't dropped when the time is over?

Here ism y code:

// TIMER

var time1:int=60;
var myTimer1:Timer = new Timer(1000, time1);

myTimer1.addEventListener(TimerEvent.TIMER, timeRunning1);
myTimer1.addEventListener(TimerEvent.TIMER_COMPLETE, timeIsUp1);

function timeRunning1(event:TimerEvent): void
{
    timer_txt.text= String(time1 - myTimer1.currentCount);
}

function timeIsUp1(event:TimerEvent): void
{
event.target.removeEventListener(MouseEvent.MOUSE_DOWN, pickUp1); // remove listener when time is over
event.target.removeEventListener(MouseEvent.MOUSE_UP, dropIt1); // remove listener when time is over
gotoAndStop("tryAgain");
  
}

// FUNCTION DRAG

function pickUp1(event:MouseEvent):void {
event.target.startDrag(true);
event.target.parent.addChild(event.target);
startX1 = event.target.x;
startY1 = event.target.y;

// I tried this to stop the drag action when time is over, but didn't work

if (time1 ==1 ) {this.event.target.visible=false; this.event.target.buttonMode=false; this.event.target.x=event.target.x; this.event.target.y=event.target.y}
}

// FUNCTION DROP

function dropIt1(event:MouseEvent):void {
event.target.stopDrag();
var myTargetName:String = "btn_" + event.target.name;
var myTarget:DisplayObject = getChildByName(myTargetName);
if (event.target.dropTarget != null && event.target.dropTarget.parent == myTarget){
  txt.text ="Good Job!";
  count++;
  score_txt.text= String(count);
  event.target.removeEventListener(MouseEvent.MOUSE_DOWN, pickUp1);
  event.target.removeEventListener(MouseEvent.MOUSE_UP, dropIt1);
  event.target.buttonMode = false;
  event.target.x = myTarget.x;
  event.target.y = myTarget.y;
  checker0++;
  myTimer1.start();
}
else {
  txt.text = "Try Again!";
  event.target.x = startX1;
  event.target.y = startY1;
}
if(checker0 == 3){
        txt.text = "Congratulations. Continue playing!";
    nav_0.visible=true;
   
   
    }

}

// ACTIVATING BUTTON

great_1.buttonMode=true;
less_1.buttonMode=true;
equal_1.buttonMode=true;

Sincerely,

German