Immolate

I have a helm with "Socketed Gems are Supported by Level 16 Immolate"

When I place a minion gem in this helm the minion tooltip does not change and no letter icon appears to indicate the skill is supported by Immolate.

If I add a level 1 Immolate gem to the same helm the minion tooltip now shows an "m" icon and the tooltip reports "Minions Deal 42-63 Added Fire Damage Againt Burning Enemies"

Is this a tooltip bug or is the Immolate affix on my helm not working?

I have burning damage socketed in my chest for specters. I had zombies in this helm. Was hoping the immolate would buff them vs burning enemies from the specter totems.

How does this gem interact with ignite and burn? I would assume that once an enemy is ignited, hitting it again would include the Immolate buff as part of the base fire damage for the new ignite?

I've liked the concept, but I do worry that it's a bit on the underwhelming side, possibly.

Namely, the way that it scales: checking compared to the required level with other fire spells, I've noticed that it consistently provides the equivalent of about 39-39.9% or so "more" damage in terms of base damage, which is problematic for two reasons when we compare it to existing supports.

For the main reference, my RF caster uses Flame Surge coupled with this gem; I can confirm that it works as I thought it would: Surge adds the base damage from Immolate to its own, THEN multiplies it with its own included "50% more," but in SPITE of having what appears, at first blush, to be a form of "double dipping," it's still underwhelming, and cannot compete with Scorching Ray in the same setup. As for the things that directly deal with the support gem:

• There are other often-used supports that are more powerful; at level 20, Controlled Destruction is worth 44% more, Elemental Focus 49% more, and Elemental Damage with Attacks a whopping 54% more.
  
  
• Even after accounting for that... Immolate doesn't improve my damage if I use a Vaal'd level 21 gem, nor does it stack on top of any other flat damage I might be gaining from my items or abyssal jewels. By contrast, those "more" multipliers from the other gems DO stack with it.
  
  
• In short, it can be very potent if you use it at low levels (while somehow having the ability to consistently have enemies burn at a measly level 38) but definitely loses its potency later on.

To be honest, I think that the balance shift necessary to make it truly viable (rather than mostly a lark) wouldn't be that big; a slight shift to make it competitive at higher levels would be sufficient; e.g, 231-347 damage (e.g, equivalent to about a "45% more") at level 20 would probably help enough. I might actually cut the damage at level 1, and have it scale more aggressively. (e.g, rather than matching equal to a "~40% more" at any spell of equivalent level, have it gradually shift from a 35% to 45% or so)

Immolate should give a more multiplier to ignite or lower fire resistance.
It's kinda weird that you deal the most ignite damage for example Burning Arrow with Tempest Bow and Lightning Damage, which comes with free Elemental Equilibrium and the ability to get full shock effectiveness while being an Elementalist.

Immolate could use some improvements
Since 3.7 flat damage buff, 3.8 global + to skill levels the support is just underpowered.
Something like
"Burning from ignite applied by supported skill deal damage (20-100)% faster"
or
"Supported skills deal fire-only splash damage" (like EH does)
would make the support a lot more interesting.

Awakened Immolate would be nice because it is out classed by every Awakened Added Damage gem regardless if the target is burning or not. So even if I am making a build to use Immolate, it is not worth using over any other Awakened Added Damage gem.

Infernal Legion Skeletons --> Immolating Summon Raging Spirits

This gem feels very weak right now.