Armored Assault is a Level 16 talent that says: While Maiev has positive Armor of any kind, all Physical Damage dealt is increased by 25%.
Since W cleave damage is physical, it should be increased by 25% against all targets when Armored Assault is active.
However, Maiev’s W cleave only does 20% increased damage to non-primary targets when Armored Assault is active.
Here is a video I made in Try Mode to illustrate the bug: https://youtu.be/NYNQqEeH1yg.
Maiev is at Level 20 with Shadow Armor picked for the Level 13 talent and Armored Assault picked for the Level 16 talent.
- The first part of the video shows that the cleave damage without any buffs is correctly 318 to all targets (display is rounded up from 317.9).
- After, I activate Armored Assault by blinking (Shadow Armor gives me armor), then use W to cleave the target dummies. While the primary target takes 397 damage, which is correctly 25% higher than base, the non-primary targets take 382 damage, which is only 20% higher than base.
I think the cause of the bug is simple. Armored Assault was once weaker, only increasing physical damage by 20%. After it got buffed to 25% on 09/27/2021, the cleave damage was not buffed along with it.