In the default language (probably the OS language), Paper2D assets will not be localized.
At the timing (FEnginePackageLocalizationCache :: FindLocalizedPackages) when the localization function extracts each asset path of L10N or less through AssetRegistry immediately after startup, the CustomVersion information of Paper2D was not loaded yet. Specifically, the GUID of CustomVersion of Paper2D is not registered in the Queue of FStaticCustomVersionRegistry of CustomVersion.cpp.
This issue is resolved by changing Paper2D's LoadingPhase to PostConfigInit.
expect : You can see the assets (rabbit picture) localized in 1 and 5.
result : You can see coin image in 1 and 5.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-146479 in the post.