Steps to reproduce:
1. Create a project
2. Create VFX Graph Asset (Create > Visual Effects > Visual Effect Graph)
3. Select one of the VXG Graph Templates (ex. Simple Trail)
4. Press on the Color gradient to open HDR Gradient Editor window
5. Press several times below the gradient to create few markers
6. Drag one of the markers downwards to remove it and observe
Actual results: All of the newly created markers disappear
Expected results: One of the markers disappears
Reproducible with versions: 6000.0.43f1, 6000.1.0b11, 6000.2.0a7
Not reproducible with versions: 2021.3.50f1, 2022.3.60f1, 6000.0.42f1
Tested on (OS): macOS Sequoia 15.3 (Intel)