How to reproduce:
1. Create a new project
2. In the Package Manager, install the Addressables package
3. In the menu bar, select “Window → Asset Management → Addressables → Groups”
4. In the Addressables Groups window, select “Create Addressables Settings”
5. In the Project window, select “Assets/AddressableAssetsData/AddressableAssetSettings”
6. In the Inspector, turn on the “Enable Json Catalog” option
7. Observe the Console

Actual result: Error CS0104 is thrown in the Console
Expected result: No errors are thrown in the Console

Reproducible with: 2.9.0 (6000.0.71f1), 2.9.1 (6000.0.71f1, 6000.3.0a3)
Not reproducible with: 2.8.1 (6000.0.71f1), 2.9.1 (6000.3.0a4, 6000.6.0a1)
Could not test with: 2.10.0 (UUM-138129)

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Note: Full error message: “Library\PackageCache\com.unity.addressables@8460f1c9c927\Editor\Build\DataBuilders\BuildScriptPackedMode.cs(933,49): error CS0104: 'BuildCompression' is an ambiguous reference between 'UnityEditor.Build.Content.BuildCompression' and 'UnityEngine.BuildCompression'“