To reproduce:
1. Open attached project
2. In the Main menu press Test > Test
3. In the Test window click on "Set to Android/Cardboard"
4. Go to Player settings in XR Settings
5. Observe Cardboard (Missing from build)

Actual result: Cardboard is missing from build when setting thought the script.
Expected result: The "Missing from build" message should not appear

Workaround: Detele Cardboard and add it again in XR settings

Reproduced in: 2017.2.3p1; 2017.3.2f1; 2017.4.5f1; 2018.1.7f1; 2018.2.0b10; 2018.3.0a3;