May be more difficult to test in 2019.3.0b2+ as recording a new animated clip in timeline is broken. (Case 1183235)
However this bug appears to not be a regression.

1. Create a new project.
2. Ensure the Timeline package is installed. (Window -> Package Manager)
3. Create a GameObject in scene. (i.e. GameObject -> 3D Object -> Cube)
4. Open the Timeline window. (Window -> Sequencing -> Timeline)
5. Select the GameObject created in Step 3 and click 'Create' in the Timeline window.
6. Make a quick animation by clicking the record button.
7. Click the curves icon next to the record button to expand the animation curves.
8. Undo the action. (Edit -> "Undo Timeline Show Inline Curves")

Expected Outcome: Expansion of the curves is undone.
Actual Outcome: Nothing happens.

GIF & simple project attached.

Reproducible in 2019.3.0b5, 2017.4.32f1, not regression.