Garbage when changing outlineColor

I seem to be getting a little bit of garbage when I modify outlineColor.

I am 'pulsating' some of my text, and in update() I'm lerping .color, .fontSize and .outlineColor like this:

        TheText.fontSize = Mathf.SmoothStep(fromSize, toSize, t);

        TheText.color = Color32.Lerp(fromTextColor, toTextColor, t);

        TheText.outlineColor = Color32.Lerp(fromTextColor, toTextColor, t);

The size and color don't generate any garbage, but the outlineColor does seem to,...

Garbage when changing outlineColor