Hi everyone, I have a question about two apex triggers in our org. The first works as expected. Here's the code:

trigger LinkToInstallation on Plan_Design_Detail__c (before insert, before update) {
  
    set<ID> salesSummaryIds = new set<ID>();
    Map<Id, Id> SCInsMap = new Map<Id, Id>();
  
    for(Plan_Design_Detail__c pdd: trigger.new){
        if(pdd.Sales_Summary__c!= null){
            salesSummaryIds.add(pdd.Sales_Summary__c);
        } 
    }
    if(!salesSummaryIds.isEmpty()){
        // prepare Inst - SC Map
        for(Installation__c ins: [select Id, Sales_Summary__c
                                          from Installation__c
                                          where Sales_Summary__c  IN :salesSummaryIds]){
            SCInsMap.put(ins.Sales_Summary__c, ins.Id);
        }
        for(Plan_Design_Detail__c pdd: trigger.new){
            pdd.Installation__c = SCInsMap.get(pdd.Sales_Summary__c);
        } 
    }
                                                      
}

This trigger involves three objects - Sale Confirmations (api name is Sales_Summary__c), Plan Design Details, and Installation. A Sale Confirmation is always created first, then a Plan Design Detail record, then an Installation record. Plan Design Details and Installations are both related to Sale Confirmations. The action this trigger does is link the Installation to the Plan Design Detail record based on the related Sale Confirmation. Once the Installation record is created the Plan Design Detail can be refreshed and the Installation record will be linked.

The second does not work as expected. I recreated the above, except it's for a new object called CBA. I need it to function in the same way. Here's the code:

trigger LinkToInstallation2 on CBA__c (before insert, before update) {
  
    set<ID> salesSummaryIds = new set<ID>();
    Map<Id, Id> SCInsMap = new Map<Id, Id>();
  
    for(CBA__c cba: trigger.new){
        if(cba.Sale_Confirmation__c!= null){
            salesSummaryIds.add(cba.Sale_Confirmation__c);
        } 
    }
    if(!salesSummaryIds.isEmpty()){
        // prepare Inst - SC Map
        for(Installation__c ins: [select Id, Sales_Summary__c
                                          from Installation__c
                                          where Sales_Summary__c  IN :salesSummaryIds]){
            SCInsMap.put(ins.Sales_Summary__c, ins.Id);
        }
        for(CBA__c cba: trigger.new){
            cba.Installation__c = SCInsMap.get(cba.Sale_Confirmation__c);
        } 
    }
                                                      
}

When I refresh the CBA record after creating the Installation the link is not there. However, if I edit and save the CBA record the link is made. I thought I could replace all the appropriate fields in the trigger and it would function the same but I'm finding that isn't the case. Does anyone have any ideas? Thank you very much!