To Reproduce:

1. Create an asset in a project with .meta files turned on
2. Add a label to the asset and save the project
3. View the asset in the Inspector
4. Open the .meta file in a text editor, remove the 'labels:' block, and save the file
5. Return to Unity and notice that the label in the Inspector does not change
6. Force-reimport the asset and note that the label still does not change