Reproduces on 2020.2.0b2, 2021.1.0a1 (didn't check on other versions)

How can we reproduce it
1 Create new project
2 Drag and Drop any .png or .jpg file from Windows Exprorer to Project Browser
3 Close the Editor
4 Open project again, go to Project Browser and "Reimport" that .png or .jpg file 3 times in a row
5 Open Editor.log
Actual Results: ConsistencyChecker logs are there, somtheng like:
"ConsistencyChecker - guid: 54a08dd6243aca6458dade0f01319e33, dependenciesHash.value: 4d1c1171da852bd8782806160f9fdb00, artifactid: 813509fedda1aea4e033ebb4c3eb8528, producedFiles[0].extension: , producedFiles[0].contentHash: cdd351f860c02a27df53477c543f14ea

ConsistencyChecker - guid: 54a08dd6243aca6458dade0f01319e33, dependenciesHash.value: 4d1c1171da852bd8782806160f9fdb00, artifactid: fabdd86fcad966d901ae293ed43f9dae, producedFiles[0].extension: , producedFiles[0].contentHash: 578789a9493d84c1edd4753592c9d9d2"

Expected Results: there should not be ConsistencyChecker logs/inconsistency

Note: the same happens with prefabs:
1 Create new project
2 Go to Hierarchy and create a Cube and a Spheres
2 Make Sphere child of the Cube
3 Drag and Drop Cube object to the Project Browser so it became a prefab
4 Go to Project Browser and "Reimport" that Cube prefab - no logs in the Console
5 Close the Editor
6 Reopen the same project
7 Go to Project Browser and "Reimport" that Cube prefab

Actual results: the log appears in the Console
"Importer(PrefabImporter) generated inconsistent result for asset(guid:11783044b13456840a43c85153893f4d) "Assets/Cube.prefab""

Expected results: import results should be consistent, so no logs should appear in the Console