How to reproduce:
1. Open the user's attached project "CrossFadeBugTest.zip"
2. Select the "Cube" GameObject and press Play
3. Press the Return/Enter key
4. Observe the animation state's progress bars in the Animator window
5. Press Spacebar
6. Repeat step 4
Expected result: Animation states play out simultaneously
Actual result: Current animations state gets paused until the other state plays out
Reproducible with: 1.0.0, 1.0.2, 1.2.0 (2019.4.37f1, 2020.3.32f1), 1.3.0 (2019.4.37f1, 2020.3.32f1, 2021.2.17f1, 2022.1.0b14, 2022.2.0a9)
Note: Pressing the Return/Enter key triggers the CrossFade function from Update and Spacebar calls it from a New Input System callback event