Kira countering wrong ability if multiple abilities on the stack have the same source

[Tharkon]

Kira's ability counters the top-most ability with the same source id as the event that triggered it rather than the event itself.
Though in most cases this is the same, I provided an example below using Angelic Benediction where the same source can trigger twice at the same time, once targeted and once not.

init.txt for testing
battlefield:Human:Angelic Benediction:1
battlefield:Human:Steadfast Guard:1
battlefield:Computer:Kira, Great Glass-Spinner:1

Attack with the guard, make sure you order the triggers so that exalted is at the top of the stack.

[jeffwadsworth]

[[Kira, Great Glass-Spinner]] [[Angelic Benediction]] [[Steadfast Guard]]

[github-actions]

Kira, Great Glass-Spinner - (Gatherer) (Scryfall) (EDHREC)

{1}{U}{U}
Legendary Creature — Spirit
2/2
Flying
Creatures you control have "Whenever this creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability."

Angelic Benediction - (Gatherer) (Scryfall) (EDHREC)

{3}{W}
Enchantment
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever a creature you control attacks alone, you may tap target creature.

Steadfast Guard - (Gatherer) (Scryfall) (EDHREC)

{W}{W}
Creature — Human Rebel
2/2
Vigilance (Attacking doesn't cause this creature to tap.)

[xenohedron]

Scryfall search for other potentially affected cards - 10 total