Sprite color reverts to original value in between Update calls

In an update method, I am calling t$$anonymous$$s:

 var projectileSpriteRenderer = currentProjectile.GetComponent<SpriteRenderer>();
 Debug.Log($"Alpha of {currentProjectile.GetInstanceID()} currently 
 {projectileSpriteRenderer.color.a}");
 var percentageOfRequiredEnergy = player.AccumulatedEnergy / player.QueuedSpells[CurrentSpell].EnergyCost;
 var lessThanOne = percentageOfRequiredEnergy < 1f;
 var newAlpha = lessThanOne ? percentageOfRequiredEnergy * .75f : 1f;
 projectileSpriteRenderer.color = new Color(1, 1, 1, newAlpha);
 Debug.Log($"Alpha now {projectileSpriteRenderer.color.a}");

If I force newAlpha to always be 0, I get the following logs every Update call:

 Alpha of -94778 currently 1
 Alpha now 0

The subject sprite is fully visible in the game and when I inspect it in the Editor, the alpha is at 100%. If I change the alpha in the Editor and then close the color picker, the alpha immediately reverts to 100%. T$$anonymous$$s means that in between calls to Update where the alpha is being changed, for some reason the value is reverting to that of the Prefab. If I change the prefab alpha to 50%, it logs somet$$anonymous$$ng like:

 Alpha of -95248 currently 0.5019608
 Alpha now 0

T$$anonymous$$s exact same code was working earlier and now doesn't, for what is as far as I can tell literally no reason.