【Unity】An asset is marked with HideFlags.DontSave but is included in the build

An asset is marked with HideFlags.DontSave but is included in the build:

Building - Failed to write file: BuildPlayer-XXXX.sharedAssets

Error building Player: Couldn't build player because of unsupported data on target platform.

BuildPipeline.BuildStreamedSceneAssetBundleで
シーンファイルをアセットバンドル化しようとした時に遭遇

2つ以上の同名のシーンファイルを1つのアセットバンドルに含めようとしたところ発生