CrossFadeAlpha - can someone explain this peculiarity?

Had the same problem with Unity 5 as well. Had submitted a bug back then, but tbh I am not sure if it is a bug or if I am missing something. Now using 2018.3.

The CrossFadeAlpha function refused to work for my text. After a few hours of headache testing various different things and googling to no avail I managed to make it work by setting...

CrossFadeAlpha - can someone explain this peculiarity?