Text Animator Bug when Amount is set to -100 with Animator props such as Opacity & Fill/Stroke Color

Specifically, the Opactiy Animator property does not interpolate/animate between selected and unselected states and vice versa. When the Fill Color Animator Property is applied, it introduces strange color output.

Here's the link to the Screen Recording showing me reproducing the Bug.

Screen Recording 

Here's a screen grab of my set up - End prop's keyframe goes from 0 to 100.