This has been working in production for around a year and suddenly it stopped working over the weekend. 

below is the initialization section of the OpportunityControllerExtension

followed by the debugging log showing the error.

I've highlighted the offending line of code in RED.

This same code worked in Prod up until this weekend, and the same code also works perfectly in Sandbox. 

I have users who are up in arms, so any help would be appreciated.

Thanks,

Mike

public with sharing class OpportunityControllerExtension {

   private final Opportunity opp;
   private final Opportunity currentOpportunity;
   private final Account billingAccount;
   private final Account agency;
   
   private aaWSDLBeans.CampaignInfo[] campaignInfo;
   private List<OpportunitySplit> splitList;
   private List<OpportunityPartner> agencyList;
   private List<Revenue_Forecast__c> newRevenueForecasts;
   public  boolean debug;
   
   public OpportunityControllerExtension(ApexPages.StandardController stdController) {
      currentOpportunity = (Opportunity)stdController.getRecord();
      debug = false;
      this.opp = [
         SELECT
              o.StageName
            , o.Name
            , o.Estimated_Revenue_Start_Date__c
            , o.Estimated_Revenue_End_Date__c
            , o.campaign_total__c
            , o.OwnerId
            , o.AccountId
            , o.AutoIO__c
            , o.I_O__c
            , o.PO__c
            , o.account.type
            , o.account.Category__c
            , o.account.sub_category__c
            , o.billing_io_key__c
            , o.account.platform_id__c
            , o.account.agency_name__r.id
            , o.account.agency_name__r.name
            , o.account.parent.name
            , o.account.name 
            , o.account.owner.name 
            , o.account.Primary_Campaign_Manager__c 
            , o.account.owner.email 
            , o.account.BillingStreet 
            , o.account.CS_Login_First_Name__c 
            , o.account.BillingCity 
            , o.account.CS_Login_Last_Name__c  
            , o.account.BillingState 
            , o.account.Website 
            , o.account.BillingPostalCode 
            , o.account.Account_Email__c 
            , o.account.BillingCountry       
            , o.account.Phone       
             ,   (SELECT Month__c, Split_Owner__r.Name, Revenue__c, Split__c, Split_Revenue__c 
                    FROM Revenue_Forecasts__r order by Month__c, Split_Owner__r.Name)
         FROM Opportunity o
         WHERE o.id = :currentOpportunity.id];

      /*this.billingAccount = currentOpportunity.account;*/
      this.billingAccount = opp.account;
      this.agency = opp.account.agency_name__r;           
  
      this.splitList = [
         Select o.SplitPercentage, o.SplitOwnerId, o.SplitAmount
         From OpportunitySplit o
         Where o.OpportunityId = :currentOpportunity.id];
         
      if (splitList.isEmpty()) {
         splitList = new List<OpportunitySplit>();
         splitList.add(new OpportunitySplit(OpportunityId = opp.id, 
                           SplitOwnerId = opp.OwnerId, SplitPercentage = 100));
      }
      calcNewRevenueForecasts();
   }

12:01:11.275 (275088000)|SOQL_EXECUTE_BEGIN|[17]|Aggregations:1|select o.StageName, o.Name, o.Estimated_Revenue_Start_Date__c, o.Estimated_Revenue_End_Date__c, o.campaign_total__c, o.OwnerId, o.AccountId, o.AutoIO__c, o.I_O__c, o.PO__c, o.account.type, o.account.Category__c, o.account.sub_category__c, o.account.platform_id__c, o.account.agency_name__r.id, o.account.agency_name__r.name, o.account.parent.name, o.account.name, o.account.owner.name, o.account.owner.email, o.account.Primary_Campaign_Manager__c, o.account.BillingStreet, o.account.CS_Login_First_Name__c, o.account.BillingCity, o.account.CS_Login_Last_Name__c, o.account.BillingState, o.account.Website, o.account.BillingPostalCode, o.account.Account_Email__c, o.account.BillingCountry, o.account.Phone, o.billing_io_key__c, (select Month__c, Split_Owner__r.Name, Revenue__c, Split__c, Split_Revenue__c from Revenue_Forecasts__r order by Month__c, Split_Owner__r.Name) from Opportunity o where o.id = :tmpVar1
12:01:11.330 (330646000)|SOQL_EXECUTE_END|[17]|Rows:1
12:01:11.331 (331377000)|SOQL_EXECUTE_BEGIN|[60]|Aggregations:0|select o.SplitPercentage, o.SplitOwnerId, o.SplitAmount from OpportunitySplit o where o.OpportunityId = :tmpVar1
12:01:11.384 (384942000)|EXCEPTION_THROWN|[60]|System.QueryException: null
12:01:11.385 (385075000)|SYSTEM_MODE_EXIT|false
12:01:11.385 (385245000)|CODE_UNIT_FINISHED|OpportunityControllerExtension <init>