Hello
I'am getting this error on the below trigger can anyone help me in solving this :Apex trigger TaskUpdateLead caused an unexpected exception, contact your administrator: TaskUpdateLead: execution of AfterInsert caused by: System.ListException: Duplicate id in list: 00Q0S000002IXn2UAG: ()

trigger TaskUpdateLead on Task ( After insert) {
    Set<ID> LeadIds = new Set<ID>();
      

    
    //We only care about tasks linked to Leads.
    
    String leadPrefix = Lead.SObjectType.getDescribe().getKeyPrefix();
    
    //Add any Lead ids coming from the new data
    
    if(trigger.new!=null){
        for (Task t : Trigger.new) {
            if (t.WhoId!= null && string.valueof(t.WhoId).startsWith(leadPrefix) ) {
                
                if(!LeadIds.contains(t.WhoId)){
                    //adding unique lead ids since there can be many tasks with single lead
                    LeadIds.add(t.WhoId);
                }
            }
        }
    }
    
    //Also add any Lead ids coming from the old data (deletes, moving an activity from one Lead to another)
    
    if(trigger.old!=null){
        for (Task t2 : Trigger.old) {
            if (t2.WhoId!= null && string.valueof(t2.WhoId).startsWith(leadPrefix) )
            {
                if(!LeadIds.contains(t2.WhoId)){
                    //adding unique lead ids since there can be many tasks with single lead
                    LeadIds.add(t2.WhoId);
                }
            }
        }
    }
    
    if (LeadIds.size() > 0){
        
        
        
        List<Lead> leadsWithTasks = [select id,Activity_Count__c,Last_activity_date__c,(select id,createddate from Tasks) from Lead where Id IN : Leadids];
        
        List<Lead> leadsUpdatable = new List<Lead>();
        //set<ID> LeadIds = new Set<ID>();
        
        
        for(Lead L : leadsWithTasks){
            If(L.Last_activity_date__c == NUll || L.Last_activity_date__c != System.Today())
            {
                Set<Date> set_Uniquedate = new Set<Date>();
                integer Count = 0;
                For(Task tsk: L.tasks)
                {
                    If(!set_Uniquedate.Contains(date.newinstance(tsk.createddate.year(), tsk.createddate.month(), tsk.createddate.day())))
                    {    
                        Count = Count+1;
                        L.Last_activity_date__c = System.Today();               
                        L.Activity_Count__c = Count;
                        leadsUpdatable.add(L);
                        set_Uniquedate.add(date.newinstance(tsk.createddate.year(), tsk.createddate.month(), tsk.createddate.day()));
                    }
                }
            }
        }
         
        if(leadsUpdatable.size()>0){
            
            update leadsUpdatable;
            //update all the leads with activity count
            
        }
        
    }
}