Why does Flare have the incorrect cast aura for its damage type?

[Jonnycbad]

Flare is Fire elemental in FF4, ff7, ff11, ff13, ff14, ff15 and tactics.

[MariaArvana]

Flare is Fire elemental in FF4, ff7, ff11, ff13, ff14, ff15 and tactics.

and its non-elemental in 1, 2, 3, 4:interlude, 4:the after years, 5, 6, 8, 9, 10, 10-2, 12, 12:revenant wings and probably more that i can't remember. Its far more non-elemental than fire-aspected throughout the entire series.
As for FF14's version, I assume it's only Fire aspected so that it'd work in-line with the Astral-Fire/Umbral ice mechanics, with its non-elemental casting animation being a nod to its primary damage-type throughout the series.

heck, even Lost flare Star, which is a nod to the even stronger version version of Flare throughout the series (Flare Star) is unaspected instead of fire.

[Enla]

Flare is Fire elemental in FF4, ff7, ff11, ff13, ff14, ff15 and tactics.

Hence the 'generally'. More often than not it's non-elemental and like I stated, it's animation is likely an easter egg nod towards the spell's origins and most common history.

[Ultimatecalibur]

Flare is Fire elemental in FF4, ff7, ff11, ff13, ff14, ff15 and tactics.

Flare/Nuke only became fire elemental in the 3D versions of FF4 (in the 2D versions it is non-elemental) and all 3 of the Tactics games' versions are non-elemental.

FF7 was the first game to make it Fire Elemental and that involved them grouping it with 3 other "super" elemental spells (Freeze, Break and Tornado). FF11 expanded that group with Flood and Burst while replacing Break with Quake.

Flare only appeared in the FF13 series in Lightning Returns which was released after ARR.

Flare was only Fire Elemental in 4 games (FFMQ, FF4DS, FF7 and FF11) before FF14 while appearing in the majority as non-elemental.