[GAMEPLAY] Tiamat does not interact with any rune except lethal tempo

Riot know about this bug already, as shown here, but I wanted to add a bit more clarification regarding other runes and active item interactions.

Essentially, the Tiamat and Ravenous Hydra actives don't count as 'damaging spells or abilities' by the game, with the exception of Lethal Tempo. Though the wording of Lethal tempo and Aery are the same, (deal damage to..), Aery is NOT triggered by dealing damage with the tiamat active, but lethal tempo is.

Aery, Comet, Phase Rush, Predator, and Electrocute all can be triggered by active items such as ,, and . Even some nonactive items like and , and indirect damage from active items like can trigger these keystones (they can count as the third hit - two auto attacks and an instance of bamis damage triggers electrocute, but not two-three ticks of just bamis). Non damaging active item effects like or can count toward Electrocute or Phase Rush. Finally, the interactions with , , have inconsistent interactions. I would expect Predator to either work with both and , and not or . However, Blue smite does not proc it, while ignite does. Bamis also does not proc it.

I made a chart with some of the interactions I could find in practice tool.

STEPS TO REPRODUCE:

1. Load into a game as any melee champion with Electrocute.
2. Buy .
3. Auto attack an enemy champion twice, then immediately use the Tiamat active. EXPECTED RESULT: Electrocute fires. ACTUAL RESULT: It does not. REPRODUCTION RATE: 100%

Repeat this process (modified for each keystone) and you will find that only Lethal Tempo interacts with the Tiamat Active. All other active items that deal damage or need to hit the enemy champion do trigger their keystones as intended. Summoner spells, passive item effects, and AOE untargeted damage ( , ) are unclear as to how they should interact.

And finally, I don't know if this is related or not, but Tiamat is NOT blocked by spellshields. Ruunans also is not blocked, but Ludens and Shiv I believe are. I get the feeling this might be related to how tiamat is coded, and how/why it doesn't interact with the keystones. How it works with lethal tempo still is beyond me, though.