How to reproduce:
1. Download the "1192516-ImportLoop-Fresh.zip" project
2. Launch Unity via command line:
Unity.exe -projectPath C:\path\to\project\ -batchmode -logFile C:\path\to\project\UnityLog.txt -testPlatform editmode -testResults C:\path\to\project\TestResults.xml -forgetProjectPath -automated "-forceFullStacktrace Assert" -api-profile NET_Standard_2_0 -runTests -automated -accept-apiupdate -enablePackageManagerTraces
3. If Unity didn't freeze, launch Unity via command line again:
Unity.exe" -projectPath C:\path\to\project -batchmode -logFile C:\path\to\project\UnityLogPlaymode.txt -testPlatform playmode -forgetProjectPath -automated "-forceFullStacktrace Assert" -api-profile NET_Standard_2_0 -runTests -automated -accept-apiupdate -enablePackageManagerTraces

Actual result: Unity imports the same assets on infinite loop.
Expected result: Unity imports the assets and opens.

Reproducible with: 2019.3.0b9, 2020.1.0a11.

Notes:
- Can't test 2019.2 and lower because of compiler errors.