Black artefacts in Timeline Inspector appear when moving Signal Emitter around

Reproduction steps:
1. Create a new project
2. Create > Timeline > Timeline
3. Double-click on the newly created Asset to open Timeline window
4. Press “+” button and add Track Group
5. Press “+” button on Track Group and add Animation Track
6. Click on Animation Track kebab menu and select “Add Signal Emitter” option
7. Move Signal Emitter around the Timeline and observe the Inspector

Actual result: Black artefacts appear in the Inspector
Expected result: Nothing of note happens

Reproducible with: 1.6.5 (2021.3.57f1), 1.8.9 (2021.3.57f1, 2022.3.67f1, 6000.0.59f1, 6000.2.7f1, 6000.3.0b4, 6000.4.0a1)

Reproduced on: macOS Sequoia 15.4 (M4)
Not reproduced on: Windows 11

Note: Issue is not always immediately reproducible, sometimes leaving Editor open for a while (10-15mins) and doing 7th step again makes the issue reproducible