Ads Mediation gives "has no meta file, but it's in an immutable folder. The asset will be ignored"

I received following error message on importing Ads Mediation 8.0.0 through Package Manager

Asset Packages/com.unity.services.levelplay/Runtime/Plugins/Android/IronSource.androidlib/AndroidManifest.xml has no meta file, but it’s in an immutable folder. The asset will be ignored.

Asset Packages/com.unity.services.levelplay/Runtime/Plugins/Android/IronSource.androidlib/libs/IronSource-bridge.jar has no meta file, but it’s in an immutable folder. The asset will be ignored.

Asset Packages/com.unity.services.levelplay/Runtime/Plugins/Android/IronSource.androidlib/project.properties has no meta file, but it’s in an immutable folder. The asset will be ignored.

How can I resolve this issue?

My Drive Path is:
E:\u\Library\PackageCache\com.unity.services.levelplay@8.0.0\Runtime\Plugins\Android\IronSource.androidlib

My Unity Version is 2021.3.20f1