Issue Summary

When adding a label to a cards with no labels on already, the JSON for the card/board shows an ID for a label that's never been added to a card.

Steps to Reproduce

1. Create a new card
2. Add a new label to this card
3. Load the JSON for the card (e.g. https://trello.com/c/CARDID.json)
4. View the actions list and find the updateCard action for the label being added

Expected Results

When viewing the action actionnumber.card.idLabels should contain the ID of the new label that's been added.

actionnumber.old should include the object idLabels but it should be empty

Actual Results

When viewing the action actionnumber.card.idLabels contains the ID of the new label that's been added.

However, actionnumber.old.idLabels includes an ID even though a label wasn't added to the card previously

Workaround

None available