How to reproduce:
1. Open user's attached "ScriptableImporterBugs.zip" project
2. Open "SampleScene" Scene
3. Select all Assets from the 'Dialogues' folder in the Project window
4. Press anywhere in the Project or Hierarchy window to deselect the Assets (Make sure you don't select any Asset or GameObject)
5. Observe the Inspector window
6. After deselecting the Assets, hold CTRL and select 4 Assets from the Dialogue folder
7. Observe the Inspector window

Expected result: No Assets are shown in the Inspector window (step 5). Objects count is equal to the Assets count in the narrow selection section (step 7)
Actual result: The previously selected Assets are still shown in the Inspector window, but Objects count is 0 (step 5). Objects count is 4, while in the narrow selection section only 3 Assets are shown (step 7)

Reproducible with: 2019.1.0a10, 2019.4.1f1, 2020.1.0b13, 2020.2.0a15
Not reproducible with: 2018.4.23f1, 2019.1.0a9

Notes:
- When all Assets from the Dialogue folder are selected and then pressing on "4 Mono Behaviours" to narrow the selection in the Inspector window - object count is updated, but the narrow selection section is not
- Attached a video in edit showing all the behaviors