Reproduction steps:
1. Open the attached “repro_IN-89353“ project
2. Open the “Assets/Scene.unity“ Scene
3. In the Hierarchy, select the “Test“ GameObject
4. In the Inspector, in the “Test Component (Script)“ Component, expand the “Localize Audio List“ dropdown
5. Press the '' button
6. Observe the Console

Expected result: No errors appear
Actual result: “NullReferenceException: Object reference not set to an instance of an object“ error appears

Reproducible with: 1.0.0-pre.9 (2021.3.47f1), 1.5.3 (2021.3.47f1, 2022.3.55f1, 6000.0.33f1, 6000.1.0a10)

Reproducible on: Windows 10 (22H2), Windows 11 (24H2) (reporter’s environment)
Not reproducible on: No other environments tested

Notes:

• On 2021.3.47f1, after pressing the '' button, the dropdown UI breaks
• On 2021.3.47f1, on the 1.5.3 version of the Localization package, after pressing the ‘+' button, saving the Scene with “Ctrl + S“ button combination doesn’t work
• According to the reporter, the issue is in the “if (baseType.IsArray) BaseType = baseType.GetElementType().BaseType;” line, which is the 33rd line of the “com.unity.localization@1.5.3\Editor\UI\Localized Reference\LocalizedAssetPropertyDrawer.cs” Script