When a project is set to use a fixed frame rate via the Project Settings it is uncapped when played in editor.
Found in 4.24 Preview 2 CL#10091930
Reproduced in 4.25 Main CL#10298106
1. Create a new project.
2. Enable "Used Fixed Frame Rate" in Project Settings.
3. Show the FPS in the viewport.
4. Play in Editor.
Results: The frame rate is uncapped.
Expected: The frame rate is locked at at 30.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-84752 in the post.