Reproduction steps:

1. Open the “SpriteResolverBug” project
2. Open “SampleScene” scene
3. Select the “Main Camera” GameObject in the Hierarchy
4. In the Inspector set Category in the “Sprite Resolver” component to Animation → Face → Mouth → Male → MaleLip
5. When entering the Play Mode

Expected result: Category field stays set
Actual result: Category is set to “No Category”

Reproducible with: 6.0.0-pre.1 (2021.1.0a1), 7.0.7 (2021.3.10f1)
Not reproducible with: 5.2.3 (2020.3.39f1), 8.0.3 (2022.1.0f1), 9.0.0 (2022.2.0b8, 2023.1.0a10)
Could not test with: 8.0.0-pre.3, 8.0.2 (2022.1.0a1, 2022.1.0b16) (Errors in the Console)

Reproduced on: Windows 10