How to reproduce:
1. Open project and load Test scene
2. You can play the scene. You can see the white text over the background.
3. Stop playing, in Project window, right click on Test.sc and select "Find references..". so only the Canvas game object is selected.
4. Remove the search conditions in the Hierarchy window, in the text field to show everything again.
5. Play the scene once again

Actual result: Now the text object color is no longer visible, it is there but its color is now black, although it shows white on the Text component inspector. You can see the text in the Scene viewport. Stop playing. Text color remains black though it shows white in inspector.
Expected result: text color stays white

Workaround: project has to be reloaded

Reproducible: 5.3.6p5, 5.4.1p1, 5.5.0b4