Foulborn Choir of the Storm Special Mana Modifier not scaling with Quality

The new unique Foulborn Choir of the Storm has the line "Mana is increased by 50% of overcapped Lightning Resistance". This is tagged as a "Mana","Elemental" and "Lightning" Modifier, but does not increase with Quality for "Life and Mana Modifiers".

I believe that either
1. This is unintended behaviour
2. The mod is not supposed to be tagged Mana or
3. The mod is missing an "unscalable value" disclaimer

Steps to reproduce:
Use Fertile Catalyst on Foulborn Choir of the Storm

Related ingame Bug Report reference ID: 1.067.222.116

Here is an image for reference: