Reproduction steps:
1. Open the attached project ("TestImport.zip")
2. Open the Assets directory via File Explorer
3. Copy the "New Test SO.asset" and "New Test SO.asset.meta" files to desktop
4. Delete the "New Test SO.asset" using Unity Editor: Project window > Right-click on the "New Test SO.asset" > Delete
5. Exit the Editor
6. Reimport the copied "New Test SO.asset" and "New Test SO.asset.meta" files back to the project's Assets directory
7. Reopen the project

Expected result: When calling AssetPostprocessor.OnPostprocessAllAssets() method, the reimported asset's name is included in the "importedAssets" array
Actual result: The reimported asset's name is not included in the "ImportedAssets" array when calling AssetPostprocessor.OnPostprocessAllAssets() method

Reproducible with: 2019.4.3f1, 2019.4.29f1, 2020.2.0a15
Not reproducible with: 2018.4.36f1, 2019.4.2f1, 2020.2.0a16, 2020.3.14f1, 2021.1.15f1, 2021.2.0b4, 2022.1.0a3