Seemingly reversed naming of debuffs relative to icon in P12S

[Deathcream]

In "Anabaseios: The Twelfth Circle (Savage)" (Referred to as P12S in title due to space limitations) the debuffs applied by the cast "Engravement of Souls" have names & descriptions opposite both the typical lore convention (to my understanding) and previous mechanic convention.
In specific "Umbral Tilt", "Umbralbright Soul" and "Umbralstrong Soul" have light blue/white icons. the debuffs "Astral Tilt", "Astralbright Soul" and "Astralstrong Soul" have dark red/black. To my understanding Astral is typically meant to represent light while Umbral is meant to represent dark but with these debuffs this convention seems flipped.
For an example of a naming parallel the debuffs in "Eden's Verse: Iconoclasm" applied by the cast "Unjoined Aspect" applies either a light blue/white debuff called "Astral Effect" or a dark purple/black debuff called "Umbral Effect" following the typical assumption of Astral-Light and Umbral-Dark, the "Astral Tilt" and "Umbral Tilt" are most parallel to these as their function is virtually identical while their naming is flipped. As an example "Astral Effect" amplifies damage received by light (white) attacks and reduces damage taken by dark (purple) attacks in the fight while "Astral Tilt" amplifies damage received by dark (red/black) and allows the player to mitigate light (white) towers

As examples of both of these I was able to take this image of "Astral Effect" from doing Iconoclasm in an Unrestricted Party solo

And while I didn't remember to screenshot it while I was in the instance I was able to find this image of an example of "Astral Tilt", the cursor isn't easily visible but it's the 20 second duration debuff


To clarify these mechanically work fine but it caused confusion when discussing and understanding the debuffs as the assumed relation between name and icon was broken

Edit: Upon viewing footage of the fight the naming of the attacks also seems to follow this naming scheme being that "Astral Glow" (the hit from the Astralbright Soul debuff), "Astral Advance" (the hit from the "tower" left behind by Astralbright Soul), and "Astral Impact" (stack laser from Astralstrong Soul) are all red/black while their counterparts "Umbral Glow", "Umbral Advance", and "Umbral Impact" are all white. A secondary attack name that does not follow the same naming scheme but causes the debuffs is "Searing Radiance" (applies Umbral Tilt) and "Shadowsear" (applies Astral Tilt), being the attacks caused by the tethers from Paradeigma 2 that retain the standard Light/Dark connotation of Radiance-Light and Shadow-Dark and apply debuffs of the fitting icon and function, but opposite name. These names are just added since if the debuffs themselves are changed but these were left it would only serve to cause inconsistency within the fight's naming itself. (Searing Radiance and Shadowsear are fine to clarify, I'm just mentioning them as they are related to application of the debuffs in question)

[Rongway]

To my understanding Astral is typically meant to represent light while Umbral is meant to represent dark but with these debuffs this convention seems flipped.

The cutscene in the Bookman's Shelves (Shadowbringers Main Scenario Quests > Lv72 "Unto the Truth" > Cutscene #2) establishes the idea that Light is Umbral while Darkness is Astral.

As the chart maketh plain, our world is composed of six elements, in addition to which there exist two poles in fundamental opposition.
Astral, the active; umbral, the passive.
As a reflection of the source, the First naturally compriseth the selfsame forces, yet curiously, there is a notable divergence in their nomenclature. To be specific, the denizens of this world employ not the terms astral and umbral.
Thus was I moved to inquire what names said forces had been assigned. A simple question which yielded a most unexpected answer...
Upon demanding the name of the pole aligned with activity and growth, I was told that as life's myriad colors combine to produce black, the people of the First had called it "Darkness." At this did my mind begin to race.
Yet 'twas only when I asked what name had been given to the pole aligned with passivity that mine eyes were opened to the truth. Peace and tranquility being as purest white unmarred by color, I was told, it had been given the name of "Light."

That's umbral light and astral darkness, yes? ...I'm no aetherologist, but it strikes me that the nomenclature of the First is rooted in the generation of the two forces, while our own appears to focus on their effects. Which makes one wonder...have we had it backwards all this time?

[Reinhardt_Azureheim]

Rongway said it perfectly, yeah.

Astral is chaos/activity, Umbral is order/stasis. To refer to our deities in-game, Zodiark is Astral, Hyadelyn is Umbral which are the two deities we referred to with Darkness and Light respectively.

[Deathcream]

Ah I see, definitely missed that mention then when going through the Main Scenario Quests, although even assuming the most recent ones are proper it does make me wonder why Iconoclasm has them flipped given it was also created after such presumably (in regards to development) and is present in the First where such a relation was made.
Checking with a friend on the Japanese versions of the debuffs it seems Twelfth Circle doesn't explicitly use light/dark, but Iconoclasm does seem to being "偏属性 : 光" (Equivalent to Astral Effect) and "偏属性 : 闇" (Equivalent to Umbral Effect) seeming to still relate Astral-Light and Umbral-Dark even when being past such in story (not sure if the Eden raids mentioned something to explain this.)
Twelfth Circle in comparison apparently uses "極性偏向 : 霊" (Equivalent to Umbral Tilt) and "極性偏向 : 星" (Equivalent to Astral Tilt) which from what I understand the last word is effectively "Spirit" for the Light, Umbral debuff and "Star" for the Dark, Astral debuffs

Regardless of which (or even both if something allows for such) are proper, it seems odd the naming convention was retained in English but not Japanese (unless I'm misunderstanding the Japanese debuff name which is very possible) while flipping it from a previous iteration without seeming reason for such flip, since both Iconoclasm and The Twelfth Circle exist at a point after that Main Scenario quest in a player's experience, unless there is something past such a point that explains it (which it's very possible I could've missed such)