Reproduction steps:

1. Open the “TimelineRepro” project
2. Open “SampleScene” scene
3. Open Timeline window by Windows → Sequencing → Timeline
4. In Hierarchy select “Main Camera” GameObject
5. In the Timeline window while holding CTRL click on the “Control Track” track, “Square” and “Square (1)” on the timeline
6. Deselect objects by clicking outside of the Control Track timeline
7. In the Timeline window select “Square” or “Square (1)”
8. Observe the Inspector

Expected result: No prompts in the Inspector
Actual result: Prompt in the Inspector - “Components that are only on some of the selected objects cannot be multi-edited”

Reproducible with: 1.7.1 (2022.1.0a12, 2022.1.12f1, 2022.2.0b3, 2023.1.0a4)
Not reproducible with: 1.4.8 (2020.3.37f1), 1.6.4 (2021.3.7f1), 1.7.0-pre.2, 1.7.0 (2022.1.0a11)

Reproduced on: Windows 10

Note: The problem is probably contained in the editor rather than in the package