In SceneTemplateAsset preset Element is added and then removed on selecting "Add to List" button from the Dependencies list, refer attached video.

Steps to repro:
1. Create a New Project
2. Project > Scene Template.
3. Select Scene Template and create Preset.
4. Select Scene Template Preset > Dependencies > Add to List (+).

Actual Result:
Element is added and then removed on selecting "Add" button from the Dependencies list

Expected Result:
Add to List works gracefully.

Reproducible on:
2020.2.0a15

Note:
Scene Template feature introduced in 2020.2.0a15

Environment:
Mac 10.15.