Shadowburn Spell Illumination Question

Hey, fellow Locks! I have a question. On some other classes I play when an ability is empowered (such as Ice Lance) or available by proc, the spell on my toolbar glows. Is Shadowburn supposed to be illuminated when the target is below 20% so you know when it gains the 50% Critical Strike chance?

If this is not the case, I would hope that in the WWI this simple/minor quality of life change will be implemented. Especially given that Shadowburn is getting additional “execute” type mechanics as in the days of old, it would be nice when hitting it will really get the most value out of the GCD/Soul Shard.

Looking for feedback, as maybe this is a UI issue on my Lock, but given how many other abilities get the associated glow, I assume this just isn’t implemented for Shadowburn.