Blue coloration (CC applied) on enemies is inconsistent when using overlapping CC.

I have noticed that when a player overlaps two different CC spells, that the enemies sometimes remain CC'd but lose their light blue coloration.

– Steps to reproduce: –

1. Start a fight with a high health enemy
2. Use Hold/Mass Hold to apply the first CC (repeat until CC is applied)
3. Observe that all CC'd enemies now have a blue coloration.
4. Cast 'Ice Storm' on one or more of the CC'd enemies.
5. Observe that the enemy coloration sometimes returns to normal despite the enemy remaining CC'd.

I have not seen this happen with spells other than Ice Storm - but I have also not explicitly tested all CC skills.
I would be happy to capture a video of this behavior if necessary. Thanks.