Friendly Rivalry only dealing damage from one creature

[grave atlas]

I cast [[Friendly Rivalry]] targeting a (not mutated) [[Glowstone Recluse]] and [[Inga and Esika]] as my creatures and opponent's [[sphinx of magosi]], which resulted in only 2 damage being dealt.
Forge v.1.6.58-SNAPSHOT-08.10 (forge.GuiMobile@4a8f8bcc)

[peak monolith]

https://scryfall.com/card/ltr/204/friendly-rivalry

Friendly Rivalry <:manar:292901508796645397><:manag:292901508654301185>

Instant
Target creature you control and up to one other target legendary creature you control each deal damage equal to their power to target creature you don't control.
"Forty-two, Master Legolas!" —Gimli

https://scryfall.com/card/iko/156/glowstone-recluse

Glowstone Recluse <:mana2:292901509060886528><:manag:292901508654301185>

Creature — Spider
Mutate (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Reach
Whenever this creature mutates, put two +1/+1 counters on it.
2/3

https://scryfall.com/card/mom/229/inga-and-esika

Inga and Esika <:mana2:292901509060886528><:manag:292901508654301185><:manau:292901508754702338>

Legendary Creature — Human God
Creatures you control have vigilance and ": Add one mana of any color. Spend this mana only to cast a creature spell."
Whenever you cast a creature spell, if three or more mana from creatures was spent to cast it, draw a card.
4/4

https://scryfall.com/card/w17/12/sphinx-of-magosi

Sphinx of Magosi <:mana3:292901508771610624><:manau:292901508754702338><:manau:292901508754702338><:manau:292901508754702338>

Creature — Sphinx
Flying
: Draw a card, then put a +1/+1 counter on Sphinx of Magosi.
"A riddle is nothing more than a trap for small minds, baited with the promise of understanding."
6/6

[manic sorrel]

will be fixed