Apex Trigger Test Failing

Trigger:

trigger AccountStatusUpdate on Contact (after update) {
    System.debug('ACCOUNT STATUS TRIGGER: starting trigger now');
    // create list for account Ids
    List<Id> accIds = new List<Id>();
    // loop through Contacts from the trigger
    for (Contact con: Trigger.new){
        // if updated Contact is a primary contact
        if(con.Primary_Contact__c == true){
            // add each Contact's Account to list of Account Ids
            accIds.add(con.AccountId);
        }
        System.debug('ACCOUNT STATUS TRIGGER: here is list of Ids related to a contact you edited: '+accIds);
    }
    //find map holding Acccounts that have Id included in list of Account Ids created above
    Map<Id,Account> accMap =  new Map<Id,Account>([SELECT Id, Intro_Call__c, Intro_Call_Date__c, Follow_Up_Date__c, Sent_1st_Access_Date__c FROM Account WHERE Id IN: accIds]);
    // create list of Accounts to update at the end of the process
    List<Account> accountsToUpdate = new List<Account>();
    System.debug('ACCOUNT STATUS TRIGGER: created accountsToUpdate List to update at the end of this process');
    // create temp Account for placeholding during the following for loop
    Account tempAccount;
    System.debug('ACCOUNT STATUS TRIGGER: creating tempAccount');
    // loop through the Contacts from the trigger
    for (Contact con: Trigger.new){
       // check again if primary contact
       if(con.Primary_Contact__c == true){
        // check for change in Intro Date value
            if(Trigger.oldMap.get(con.Id).Intro_Call_Date__c != con.Intro_Call_Date__c){
                tempAccount = accMap.get(con.AccountId);
                tempAccount.Intro_Call_Date__c = con.Intro_Call_Date__c;
                tempAccount.Intro_Call__c = true;
                accountsToUpdate.add(tempAccount);
                System.debug('ACCOUNT STATUS TRIGGER: adding Intro Call and Intro Call Date values to tempAccount variable');
            } 
            if(Trigger.oldMap.get(con.Id).Intro_FollowUp_Date__c != con.Intro_FollowUp_Date__c){
                tempAccount = accMap.get(con.AccountId);
                tempAccount.Follow_Up_Date__c= con.Intro_FollowUp_Date__c;
                accountsToUpdate.add(tempAccount);
                System.debug('ACCOUNT STATUS TRIGGER: adding Followup Date value to tempAccount variable');
            } 
            if(Trigger.oldMap.get(con.Id).Sent_Access__c != con.Sent_Access__c){
                tempAccount = accMap.get(con.AccountId);
                tempAccount.Sent_1st_Access_Date__c = con.Sent_Access__c;
                accountsToUpdate.add(tempAccount);
                System.debug('ACCOUNT STATUS TRIGGER: adding Sent1st Access Date values to tempAccount variable');
            } 
            if(Trigger.oldMap.get(con.Id).Contact_Status__c != con.Contact_Status__c){
                if(con.Contact_Status__c == 'Active'){
                    tempAccount = accMap.get(con.AccountId);
                    tempAccount.Partner_Status__c = 'Active';
                    accountsToUpdate.add(tempAccount);
                    System.debug('ACCOUNT STATUS TRIGGER: changing Account status to Active because Primary POC became active');
                }
            }
        }
    }
    // if this list has any records, then update said records
    if(accountsToUpdate.size() > 0){
        update accountsToUpdate;
    } else
        System.debug('ACCOUNT STATUS TRIGGER: no Account to update at this time');
}

@isTest
public class TestAccountStatusUpdate {
    @isTest static void TESTAccountStatusWithUpdatedContactDates(){
    Account acct = new Account(Name='Test Account45', Primary_Contact__c='KenTest');
    insert acct;
    Contact con = new Contact(AccountId=acct.Id, lastName='KenKen', Primary_Contact__c=true);
    insert con;
    Test.startTest();
    con.Intro_Call_Date__c=Date.today()+1;
    con.Intro_FollowUP_Date__c=Date.today()+1;
    con.Sent_Access__c=Date.today()+1;
    con.Contact_Status__c='Active';
    update con;
    Test.stopTest();
    }
}

Error:

System.DmlException: Update failed. First exception on row 0 with id 003r000000L4KLeAAN; first error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, AccountStatusUpdate: execution of AfterUpdate
caused by: System.ListException: Duplicate id in list: 001r000000I74iXAAR
Trigger.AccountStatusUpdate: line 61, column 1: []