[2D] [Animation] Sprite not found in SpriteRenderer when moving between 2 keys with different Labels in Sprite Resolver

Steps to Repro:
1. import two character PSDs and prep them for sprite swapping (rig one, paste rig data to other, define Categories)
2. create a SpriteLibrary asset that uses the same Categories as the character PSDs
3. set each Category List to 2 and add the sprites from both character PSDs into the proper Category
4. add a character to the scene, attach an Animation component, and choose the combined SpriteLibrary Asset
5. add Bone and Sprite properties in Animation and create 2 keys
6. set 1 key to use one Category Label and set the second to use the other Category Label
7. move the timeline between the 2 keys

The Sprite disappears and warning appears in the Sprite Skin inspector (Sprite not found in SpriteRenderer).

https://i.gyazo.com/d1e46331e436bbb5e320a78cb60a5ecf.gif