I cannot figure out for the life of me how PackId is undefined according to the error: TypeError: Cannot read property 'PackId' of undefined.

What I'm doing here is: I'm deleting an object that's inside of a collection (which's happening successfully) but I'd also like to eventually display the response correctly which should consist of packIdsOwned and packsOwnedMetadata arrays being populated.

Why's PackId null in the packIdsOwned.push(packsOwned[i].PackId); line and how can I fix it?

const db = client.db("myDb");
let collection = db.collection("Players");
let result = null;
let packIdsOwned = [];
let packsOwnedMetadata = [];
let packIdInput = Profile.PackIdInput; // user input

let packsOwned = result.packsOwned; 

// Delete object in the document
collection.updateOne({"userName": result['userName']}, { $pull: { packsOwned: { PackId: packIdInput }}});
          
// Remove the pack ID from the response that's been deleted in the document
for(let i = 0; i < packsOwned.length; i++) {

    if (packsOwned[i].PackId == packIdInput) {
       let removePackId = packsOwned.splice(i, 1); // find the PackId in the document and delete it
       removePackId = null;
     }

     // this is for the response but the below line is throwing off the whole program

     packIdsOwned.push(packsOwned[i].PackId); // it's saying this PackId value is null
     packsOwnedMetadata.push({
       PackID : packsOwned[i].PackId
     });

}