Spell reduction trait not working correctly with split damage

I couldn’t find any GoW guide that has the mechanics for scatter/split damage, only this post from a player:

  • Scatter/split damage - divide all your damage, and deal them to all 4 enemies. The damage amount on each troop random, but it can take out troops if their life is less than 1/4 of your total spell power.

What I take this to mean:

  1. If calculates if any troop has less life than 1/X (X=remaining troops), and deals at least enough to kill them. (Can overkill happen? Is that what occurred in OP’s video?)
  2. Divides rest of damage “randomly”, taking above into account.

In this case, it’s very possible Tina would survive. Your Sunbird’s damage divided by 2 is 57.5, which is not enough to kill Tina due to her Spell Block trait. RNG was not on your side when it split the damage.

However… this lead me to question how random is random? It always seems to divide the damage relatively “evenly”. What I mean is that I’ve never seen it deal only 1 or 2 damage to one troop, while dealing significantly more to another troop (when no troops are killed by the cast). Just to illustrate what I mean, I tested my Sunbird in explore on Warlord IV to ensure it couldn’t kill anything on its initial casts:

Battle 1
Cast 1 = 27, 27, 22, 21
Cast 2 = 20, 16, 30, 24
Cast 3 = 15, 16 (killed), 9, 21 (Sunbird had taken health damage, so unknown total damage)

Battle 2
Cast 1 = 22, 24, 32, 19
Cast 2 = 19, 19, 25, 27

There’s certainly some randomness in there, but not completely “random”. I assume this has been talked about before, but I couldn’t find any topics about it.

EDIT: So I tried another battle to see how damage is split when a troop is killed from split damage. I didn’t keep track of how much total damage Sunbird should have dealt in my Battle 1 example.

Battle 3 (against 4 Wall of Bones)
Cast 1 = 21, 23, 32, 21
Cast 2 = 20, 27, 20, 23
Cast 3 = 27, 26, 22, 15
Cast 4 (90 dmg total) = 33, 20, 16 (killed), 21
Cast 5 = 30, 28, 32
Cast 6 = 31, 28, 31
Cast 7 (90 dmg total) = 17 (killed), 45, 28

In Cast 4 and 7, 1 troop was killed but it was only dealt the exact amount of damage needed to kill it. The rest of the damage was divided among the rest of the troops. Why did this not happen in OP’s example?

EDIT2: Further testing with 1 troop that has Spell Block.

Battle 4 (against 3 Wall of Bones and 1 Ethereal Sentry in 2nd slot)
Cast 1 = 26, 13, 20, 24
Cast 2 = 20, 12, 24, 21
Cast 3 = 31, 9, 19, 22
Cast 4 = 13, 13, 22, 29
(Health left = 12, 13, 29, 18)
Cast 5 = 12 (killed), 10, 29 (killed), 18 (killed)

Cast 5 should have had a total of 90 damage. 59 was dealt to the walls, and killed all 3. 20 was dealt to the Ethereal Sentry, resulting in 10 actual damage. Where’s the remaining 11 damage?

EDIT3: Also previously reported and discussed in this thread. It appears to be due to the fact that scatter damage never deals enough damage to overkill, so it’ll never deal enough to kill an enemy with a spell reduction trait.