Updating item SET IF_NOT_EXISTS and LIST_APPEND expected behavior

[michael-pont]

I wanted to do an update to an item which has an optional field that can be undefined or is a list of strings.
The expected behavior from the following code is that if the field doesn't exist then then a new list will be created with that particular string. If the list already does exist then an item will be appended to the list. What I found is that the order of the operation matters.

const transaction = new WriteTransaction().addUpdateItem<UserEntity>(
  UserEntity,
  {
    id: '6175f565-3988-4703-ab62-bdf947b184a0',
  },
  {
    nudgeIds: {
      SET: {
        IF_NOT_EXISTS: ['08d02911-5255-4e93-86ea-47a0b18cf78a'],
        LIST_APPEND: ['08d02911-5255-4e93-86ea-47a0b18cf78a'],
      },
    },
  },
);

In this scenario above the LIST_APPEND is never triggered even though the item already exists.
If I switch the order of LIST_APPEND and IF_NOT_EXISTS then the item gets added. However, if the item does not exist then the transaction fails because the IF_NOT_EXISTS does not get triggered first.

nudgeIds: {
  SET: {
    LIST_APPEND: ['08d02911-5255-4e93-86ea-47a0b18cf78a'],
    IF_NOT_EXISTS: ['08d02911-5255-4e93-86ea-47a0b18cf78a'],
  },
},

Is this behavior expected? Is it possible to achieve what I described?

Other Info
Using Typedorm 1.15.4