Cinemachine Blend List Camera not activating when transitioned to by a Cinemachine Mixing Camera

Reproduction steps:
1. Open the attached "repro_IN-35339.zip" project
2. Open "Assets/Scenes/SampleScene" and enter Play Mode
3. Select the "Mixing Camera" GameObject in the Hierarchy window
4. In the Inspector set "Blend List Camera" value to "1" and observe the Scene
5. Disable and enable the "Mixing Camera" GameObject and observe the Scene

Expected result: Camera starts moving from one point to another at step 4
Actual result: Camera starts moving from one point to another only after disabling and enabling the "Mixing Camera" GameObject

Reproducible with: 2.9.5 (2020.3.46f1, 2021.3.21f1), 3.0.0-pre.3 (2022.2.11f1, 2023.1.0b8, 2023.2.0a6)
Couldn't test with: 3.0.0-pre.4 (due to assembly errors)

Note: Reproducible on Editor, WebGL and Windows builds